diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters
index 77d0509..7c17f4e 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters
@@ -233,5 +233,8 @@
     <ClInclude Include="models\ComboPackage.h">
       <Filter>Header Files\Models</Filter>
     </ClInclude>
+    <ClInclude Include="utilities\Utility.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp
index b5f191e..3fdce03 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp
@@ -14,6 +14,7 @@ Date:19-May-2026
 #include "JobCard.h"
 #include "Enums.h"
 #include "User.h"
+#include "Invoice.h"
 
 /*
 Function: login
@@ -238,11 +239,20 @@ void Controller::removeComboPackage(const std::string& comboPackageID)
 
 util::Map<std::string, const Invoice*> Controller::getInvoicesByUser()
 {
-    return util::Map<std::string, const Invoice*>();
+    User* currentUser = m_authenticationManagementService.getAuthenticatedUser();
+    util::Map<std::string, Invoice*> currentUserInvoices =  m_paymentManagementService.getInvoices(currentUser->getId());
+    util::Map<std::string, const Invoice*> userInvoicesReadOnly;
+    for (int iterator = 0; iterator < currentUserInvoices.getSize(); iterator++)
+    {
+        Invoice* currentInvoice = currentUserInvoices.getValueAt(iterator);
+        userInvoicesReadOnly.insert(currentInvoice->getId(), currentInvoice);
+    }
+    return userInvoicesReadOnly;
 }
 
 void Controller::completePayment(const std::string& invoiceID, util::PaymentMode paymentMode)
 {
+    m_paymentManagementService.completePayment(invoiceID, paymentMode);
 }
 
 util::Vector<const Notification*> Controller::getNotifications()
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h
index 02aa0ec..f0c336f 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h
@@ -14,6 +14,7 @@ Date:19-May-2026
 #include "UserManagementService.h"
 #include "ServiceManagementService.h"
 #include "InventoryManagementService.h"
+#include "PaymentManagementService.h"
 
 class Service;
 class ComboPackage;
@@ -31,6 +32,7 @@ private:
     UserManagementService m_userManagementService;
     ServiceManagementService m_serviceManagementService;
     InventoryManagementService m_inventoryManagementService;
+    PaymentManagementService m_paymentManagementService;
 public:
     bool login(const std::string& username, const std::string& password);
     void logout();
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.cpp
index ba7bc84..507f274 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.cpp
@@ -16,7 +16,8 @@ Invoice::Invoice(
     const std::string& bookingId,
     ServiceBooking* booking,
     const util::Timestamp& invoiceDate, 
-    double laborCost, const util::Map<int,
+    double laborCost, 
+    const util::Map<std::string,
     InventoryItem*>& parts,
     double partsCost,
     double discountPercentage, 
@@ -63,7 +64,7 @@ double Invoice::getLaborCost() const
     return m_laborCost;
 }
 
-const util::Map<int, InventoryItem*>& Invoice::getParts() const
+const util::Map<std::string, InventoryItem*>& Invoice::getParts() const
 {
     return m_parts;
 }
@@ -123,7 +124,7 @@ void Invoice::setLaborCost(double laborCost)
     m_laborCost = laborCost;
 }
 
-void Invoice::setParts(const util::Map<int, InventoryItem*>& parts)
+void Invoice::setParts(const util::Map<std::string, InventoryItem*>& parts)
 {
     m_parts = parts;
 }
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.h b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.h
index 212d33f..f78f7c9 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.h
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.h
@@ -16,7 +16,7 @@ private:
     ServiceBooking* m_booking;
     util::Timestamp m_invoiceDate;
     double m_laborCost;
-    util::Map<int, InventoryItem*> m_parts;
+    util::Map<std::string, InventoryItem*> m_parts;
     double m_partsCost;
     double m_discountPercentage;
     double m_totalAmount;
@@ -30,8 +30,8 @@ public:
         const std::string& bookingId,
         ServiceBooking* booking,
         const util::Timestamp& invoiceDate, 
-        double laborCost, const util::Map<int,
-        InventoryItem*>& parts,
+        double laborCost, 
+        const util::Map<std::string,InventoryItem*>& parts,
         double partsCost,
         double discountPercentage, 
         double totalAmount, 
@@ -44,7 +44,7 @@ public:
     ServiceBooking* getBooking() const;
     const util::Timestamp& getInvoiceDate() const;
     double getLaborCost() const;
-    const util::Map<int, InventoryItem*>& getParts() const;
+    const util::Map<std::string, InventoryItem*>& getParts() const;
     double getPartsCost() const;
     double getDiscountPercentage() const;
     double getTotalAmount() const;
@@ -56,7 +56,7 @@ public:
     void setBooking(ServiceBooking* booking);
     void setInvoiceDate(const util::Timestamp& invoiceDate);
     void setLaborCost(double laborCost);
-    void setParts(const util::Map<int, InventoryItem*>& parts);
+    void setParts(const util::Map<std::string, InventoryItem*>& parts);
     void setPartsCost(double partsCost);
     void setDiscountPercentage(double discountPercentage);
     void setTotalAmount(double totalAmount);
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h
index 9bd78aa..1a45a24 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <string>
+#include "Enums.h"
 #include "Timestamp.h"
 #include "Enums.h"
 
@@ -7,6 +8,7 @@ class ServiceBooking;
 class Service;
 class User;
 
+
 class JobCard
 {
 private:
@@ -21,7 +23,6 @@ private:
     util::Timestamp m_assignedDate;
     util::ServiceJobStatus m_status;
     util::Timestamp m_completionDate;
-
 public:
     JobCard();
     JobCard(const std::string& bookingId,
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp
index 786ebcf..094e104 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp
@@ -1 +1,94 @@
 #include "PaymentManagementService.h"
+#include "ServiceBooking.h"
+#include "Service.h"
+#include "InventoryItem.h"
+#include "Utility.h"
+#include "Factory.h"
+#include "Timestamp.h"
+#include "Invoice.h"
+#include "JobCard.h"
+#include "Enums.h"
+
+static void createInventoryItemsMap(util::Map<std::string, InventoryItem*>& completeInventoryItemMapOfBooking, const Service* currentService)
+{
+	auto& currentRequiredInventoryItems = currentService->getRequiredInventoryItems();
+	for (int iterator = 0; iterator < currentRequiredInventoryItems.getSize(); iterator++)
+	{
+		auto& currentRequiredInventoryItem = currentRequiredInventoryItems.getValueAt(iterator);
+		completeInventoryItemMapOfBooking.insert(currentRequiredInventoryItem->getId(), currentRequiredInventoryItem);
+	}
+}
+
+void PaymentManagementService::generateInvoice(ServiceBooking* booking)
+{
+	if (!booking)
+	{
+		throw std::runtime_error("Invoice generation failed: booking is null.");
+	}
+	double totalLabourCost = 0, totalPartsCost = 0, totalServiceCost = 0;
+	double discountPercentage = booking->getDiscountPercentage();
+	std::string bookingID = booking->getId();
+	util::Map<std::string, Service*> servicesInTheBookedService = booking->getServices();
+	util::Map<std::string, InventoryItem*> completeInventoryItemMapOfBooking;
+	util::Map<std::string, JobCard*> currentJobCards = m_dataStore.getJobCards();
+	for (int iterator = 0; iterator < currentJobCards.getSize(); iterator++)
+	{
+		JobCard* currentJobCard = currentJobCards.getValueAt(iterator);
+		if (currentJobCard->getBookingId() == bookingID && currentJobCard->getStatus() != util::ServiceJobStatus::COMPLETED)
+		{
+			throw std::runtime_error("Invoice generation failed: not all job cards are completed for booking '" + bookingID + "'.");
+		}
+	}
+	for (int iterator = 0; iterator < servicesInTheBookedService.getSize(); iterator++)
+	{
+		Service* currentService = servicesInTheBookedService.getValueAt(iterator);
+		if (currentService)
+		{
+			createInventoryItemsMap(completeInventoryItemMapOfBooking, currentService);
+			totalLabourCost += currentService->getLaborCost();
+			totalPartsCost += calculatePartsCost(currentService);
+		}
+	}
+	totalServiceCost = totalLabourCost + totalPartsCost;
+	totalServiceCost -= (totalServiceCost * (discountPercentage / 100));
+	Invoice* invoice = Factory::getObject<Invoice>(bookingID, booking, util::Timestamp(), totalLabourCost, completeInventoryItemMapOfBooking, totalPartsCost, discountPercentage, totalServiceCost, util::Timestamp(), util::PaymentMode::NOTSET, util::PaymentStatus::PENDING);
+	util::Map<std::string, Invoice*>& currentInvoices = m_dataStore.getInvoices();
+	currentInvoices.insert(invoice->getId(), invoice);
+}
+
+util::Map<std::string, Invoice*> PaymentManagementService::getInvoices(const std::string& customerID)
+{
+	util::Map<std::string, Invoice*>& currentInvoices = m_dataStore.getInvoices();
+	util::Map<std::string, Invoice*> currentUserInvoices;
+	for (int iterator = 0; iterator < currentInvoices.getSize(); iterator++)
+	{
+		Invoice* currentInvoice = currentInvoices.getValueAt(iterator);
+		if (currentInvoice->getBooking()->getCustomerId() == customerID)
+		{
+			currentUserInvoices.insert(currentInvoice->getId(), currentInvoice);
+		}
+	}
+	return currentUserInvoices;
+}
+
+void PaymentManagementService::completePayment(const std::string& invoiceID, util::PaymentMode paymentMode)
+{
+	auto& currentInvoices = m_dataStore.getInvoices();
+	int invoiceIndex = currentInvoices.find(invoiceID);
+	if (invoiceIndex != -1)
+	{
+		Invoice* invoice = currentInvoices.getValueAt(invoiceIndex);
+		User* currentUser = invoice->getBooking()->getCustomer();
+		invoice->setPaymentMethod(paymentMode);
+		invoice->setPaymentDate(util::Timestamp());
+		invoice->setStatus(util::PaymentStatus::COMPLETED);
+		std::string title, message;
+		title = "Payment successful";
+		message = "Payment successful for invoice ID " + invoiceID;
+		sendNotification(currentUser, title, message);
+	}
+	else
+	{
+		throw std::runtime_error("Payment failed: invalid invoice ID.");
+	}
+}
\ No newline at end of file
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Enums.h b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Enums.h
index 5353467..f198108 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Enums.h
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Enums.h
@@ -13,7 +13,8 @@ namespace util
 	enum class PaymentMode
 	{
 		ONLINE,
-		OFFLINE
+		OFFLINE,
+        NOTSET
 	};
 
 	enum class PaymentStatus
@@ -74,6 +75,8 @@ namespace util
             return "ONLINE";
         case PaymentMode::OFFLINE:
             return "OFFLINE";
+        case PaymentMode::NOTSET:
+            return "NOTSET";
         }
         throw std::invalid_argument("Invalid PaymentMode");
     }
diff --git a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp
index 7151737..4d8c3c6 100644
--- a/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp
+++ b/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp
@@ -1,14 +1,16 @@
 #include <iomanip>
-#include "CustomerMenu.h"
+#include <iostream>
 #include "ComboPackage.h"
+#include "CustomerMenu.h"
 #include "Enums.h"
 #include "InputHelper.h"
 #include "InventoryItem.h"
+#include "Invoice.h"
 #include "Map.h"
 #include "OutputHelper.h"
 #include "Service.h"
-#include "Service.h"
 #include "ServiceBooking.h"
+#include "Timestamp.h"
 #include "User.h"
 #include "Utility.h"
 #include "Validator.h"
@@ -273,11 +275,11 @@ void CustomerMenu::selectComboPackage()
 
 void CustomerMenu::viewServiceHistory()
 {
-	util::clear();
-	bool hasServiceHistory = false;
-	const User* currentUser = m_controller.getAuthenticatedUser();
-	std::string currentUserID = currentUser->getId();
-	util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
+    util::clear();
+    bool hasServiceHistory = false;
+    const User* currentUser = m_controller.getAuthenticatedUser();
+    std::string currentUserID = currentUser->getId();
+    util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
     if (serviceBookingsByCurrentUser.getSize() != 0)
     {
         std::cout << std::left
@@ -313,12 +315,153 @@ void CustomerMenu::viewServiceHistory()
     }
 }
 
+static std::string selectInvoiceFromUserForPayment(const util::Map<std::string, const Invoice*>& currentInvoices)
+{
+    int currentIndex = 1, choice;
+    util::Map<int, const Invoice*> pendingInvoicesForPayment;
+    std::cout << std::left
+        << std::setw(6) << "Index"
+        << std::setw(12) << "BookingID"
+        << std::setw(15) << "VehicleBrand"
+        << std::setw(15) << "VehicleNumber"
+        << std::setw(12) << "TechID"
+        << std::setw(20) << "TechnicianName"
+        << std::setw(10) << "Discount(%)"
+        << std::setw(12) << "TotalAmount"
+        << std::setw(20) << "InvoiceDate"
+        << std::endl;
+    for (int iterator = 0; iterator < currentInvoices.getSize(); iterator++)
+    {
+        const Invoice* currentInvoice = currentInvoices.getValueAt(iterator);
+        if (currentInvoice && currentInvoice->getStatus() == util::PaymentStatus::PENDING)
+        {
+            std::cout << std::left
+                << std::setw(6) << currentIndex
+                << std::setw(12) << currentInvoice->getBookingId()
+                << std::setw(15) << currentInvoice->getBooking()->getVehicleBrand()
+                << std::setw(15) << currentInvoice->getBooking()->getVehicleNumber()
+                << std::setw(12) << currentInvoice->getBooking()->getAssignedTechnician()->getId()
+                << std::setw(20) << currentInvoice->getBooking()->getAssignedTechnician()->getName()
+                << std::setw(10) << currentInvoice->getDiscountPercentage()
+                << std::setw(12) << currentInvoice->getTotalAmount()
+                << std::setw(20) << currentInvoice->getInvoiceDate().toString()
+                << std::endl;
+            pendingInvoicesForPayment.insert(currentIndex++, currentInvoice);
+        }
+    }
+    if (pendingInvoicesForPayment.getSize() == 0)
+    {
+        std::cout << "No pending invoices available for payment.\n";
+        return "";
+    }
+    std::cout << "Select the Invoice to pay (Index): ";
+    util::read(choice);
+    int selectedIndex = pendingInvoicesForPayment.find(choice);
+    if (selectedIndex != -1)
+    {
+        const Invoice* selectedInvoice = pendingInvoicesForPayment.getValueAt(selectedIndex);
+        return selectedInvoice->getId();
+    }
+    else
+    {
+        std::cout << "Invalid choice.\n";
+        return "";
+    }
+}
+
+static util::PaymentMode selectPaymentMode()
+{
+    int choice;
+    std::cout << "Enter the payment Mode\n1.OFFLINE\n2.ONLINE\nChoice: ";
+    util::read(choice);
+    if (choice == 1)
+    {
+        std::cout << "Offline mode selected.\n";
+        return util::PaymentMode::OFFLINE;
+    }
+    else if (choice == 2)
+    {
+        std::cout << "Online mode selected.\n";
+        return util::PaymentMode::ONLINE;
+    }
+    else
+    {
+        std::cout << "Invalid choice, Offline mode selected.\n";
+        return util::PaymentMode::OFFLINE;
+    }
+}
+
 void CustomerMenu::completePayments()
 {
+	util::clear();
+	util::Map<std::string, const Invoice*> currentInvoices = m_controller.getInvoicesByUser();
+	std::string selectedID = selectInvoiceFromUserForPayment(currentInvoices);
+    if (selectedID == "")
+    {
+        std::cout << "Payment failed.\n";
+        return;
+    }
+    util::PaymentMode paymentMode = selectPaymentMode();
+    m_controller.completePayment(selectedID, paymentMode);
+    std::cout << "Payment completed successfully.\n";
+}
+
+static void displayInvoices(util::Map<std::string, const Invoice*> currentUserInvoices)
+{
+	if (currentUserInvoices.getSize() == 0)
+	{
+		std::cout << "No invoices found for this account." << std::endl;
+		util::pressEnter();
+		return;
+	}
+	else
+	{
+        for (int index = 0; index < currentUserInvoices.getSize(); index++)
+        {
+            const Invoice* currentInvoice = currentUserInvoices.getValueAt(index);
+            if (currentInvoice)
+            {
+                std::cout << "\nInvoice Details\n";
+                std::cout << "Booking ID: " << currentInvoice->getBookingId() << std::endl;
+                std::cout << "Vehicle Brand: " << currentInvoice->getBooking()->getVehicleBrand() << std::endl;
+                std::cout << "Vehicle Number: " << currentInvoice->getBooking()->getVehicleNumber() << std::endl;
+                std::cout << "Technician ID: " << currentInvoice->getBooking()->getAssignedTechnician()->getId() << std::endl;
+                std::cout << "Technician Name: " << currentInvoice->getBooking()->getAssignedTechnician()->getName() << std::endl;
+                std::cout << "Discount(%): " << currentInvoice->getDiscountPercentage() << std::endl;
+                std::cout << "Total Amount: " << currentInvoice->getTotalAmount() << std::endl;
+                std::cout << "Invoice Date: " << currentInvoice->getInvoiceDate().toString() << std::endl;
+                std::cout << "Payment Status: " << util::getPaymentStatusString(currentInvoice->getStatus()) << std::endl;
+                auto inventoryItemsInInvoice = currentInvoice->getParts();
+                std::cout << "\nItems Used:\n";
+                std::cout << std::left
+                    << std::setw(20) << "ItemName"
+                    << std::setw(10) << "Quantity"
+                    << std::setw(10) << "Price"
+                    << std::endl;
+                std::cout << std::string(40, '-') << std::endl;
+                for (int iterator = 0; iterator < inventoryItemsInInvoice.getSize(); iterator++)
+                {
+                    InventoryItem* currentItem = inventoryItemsInInvoice.getValueAt(iterator);
+                    std::cout << std::left
+                        << std::setw(20) << currentItem->getPartName()
+                        << std::setw(10) << currentItem->getQuantity()
+                        << std::setw(10) << currentItem->getPrice()
+                        << std::endl;
+                }
+            }
+            else
+            {
+                throw std::runtime_error("Null invoice encountered while displaying invoices.");
+            }
+        }
+	}
 }
 
 void CustomerMenu::viewInvoices()
 {
+	util::clear();
+	util::Map<std::string, const Invoice*> currentUserInvoices = m_controller.getInvoicesByUser();
+	displayInvoices(currentUserInvoices);
 }
 
 void CustomerMenu::viewNotifications()