diff --git a/Marco.Pms.Services/Controllers/CollectionController.cs b/Marco.Pms.Services/Controllers/CollectionController.cs
index 320eb74..fdcb9b8 100644
--- a/Marco.Pms.Services/Controllers/CollectionController.cs
+++ b/Marco.Pms.Services/Controllers/CollectionController.cs
@@ -1144,6 +1144,7 @@ namespace Marco.Pms.Services.Controllers
             // Create a scope for permission service resolution
             using var scope = _serviceScopeFactory.CreateScope();
             var _permission = scope.ServiceProvider.GetRequiredService<PermissionServices>();
+            var _updateLogHelper = scope.ServiceProvider.GetRequiredService<UtilityMongoDBHelper>();
 
             // Get the currently logged-in employee
             var loggedInEmployee = await _userHelper.GetCurrentEmployeeAsync();
@@ -1196,15 +1197,31 @@ namespace Marco.Pms.Services.Controllers
 
             try
             {
+                var invoiceStateBeforeChange = _updateLogHelper.EntityToBsonDocument(invoice);
+
                 // Mark invoice as completed.
                 invoice.MarkAsCompleted = true;
+                invoice.UpdatedAt = DateTime.UtcNow;
+                invoice.UpdatedById = loggedInEmployee.Id;
 
                 // Persist the change to the database.
                 await _context.SaveChangesAsync();
 
                 _logger.LogInfo("Invoice {InvoiceId} marked as completed by user {UserId}", invoiceId, loggedInEmployee.Id);
 
-                return Ok(ApiResponse<object>.SuccessResponse(new { }, "Invoice is marked as completed successfully", 200));
+                await _updateLogHelper.PushToUpdateLogsAsync(new UpdateLogsObject
+                {
+                    EntityId = invoice.Id.ToString(),
+                    UpdatedById = loggedInEmployee.Id.ToString(),
+                    OldObject = invoiceStateBeforeChange,
+                    UpdatedAt = DateTime.UtcNow
+                }, "InvoiceModificationLog");
+
+                var response = _mapper.Map<InvoiceListVM>(invoice);
+                response.UpdatedBy = _mapper.Map<BasicEmployeeVM>(loggedInEmployee);
+                response.BalanceAmount = response.BasicAmount + response.TaxAmount;
+
+                return Ok(ApiResponse<object>.SuccessResponse(response, "Invoice is marked as completed successfully", 200));
             }
             catch (Exception ex)
             {