diff --git a/packages/server/src/interfaces/PaymentReceive.ts b/packages/server/src/interfaces/PaymentReceive.ts
index 2926d923c..329d0d944 100644
--- a/packages/server/src/interfaces/PaymentReceive.ts
+++ b/packages/server/src/interfaces/PaymentReceive.ts
@@ -173,3 +173,9 @@ export type IPaymentReceiveGLCommonEntry = Pick<
 export interface PaymentReceiveMailOpts extends CommonMailOptions {}
 
 export interface PaymentReceiveMailOptsDTO extends CommonMailOptionsDTO {}
+
+export interface PaymentReceiveMailPresendEvent {
+  tenantId: number;
+  paymentReceiveId: number;
+  messageOptions: PaymentReceiveMailOptsDTO;
+}
diff --git a/packages/server/src/interfaces/SaleEstimate.ts b/packages/server/src/interfaces/SaleEstimate.ts
index 171c8a0d1..9ac17295c 100644
--- a/packages/server/src/interfaces/SaleEstimate.ts
+++ b/packages/server/src/interfaces/SaleEstimate.ts
@@ -132,4 +132,10 @@ export interface SaleEstimateMailOptions extends CommonMailOptions {
 
 export interface SaleEstimateMailOptionsDTO extends CommonMailOptionsDTO {
   attachEstimate?: boolean;
-}
\ No newline at end of file
+}
+
+export interface ISaleEstimateMailPresendEvent {
+  tenantId: number;
+  saleEstimateId: number;
+  messageOptions: SaleEstimateMailOptionsDTO;
+}
diff --git a/packages/server/src/interfaces/SaleReceipt.ts b/packages/server/src/interfaces/SaleReceipt.ts
index 1e8ffa98e..8904767c6 100644
--- a/packages/server/src/interfaces/SaleReceipt.ts
+++ b/packages/server/src/interfaces/SaleReceipt.ts
@@ -143,3 +143,9 @@ export interface SaleReceiptMailOpts extends CommonMailOptions {
 export interface SaleReceiptMailOptsDTO extends CommonMailOptionsDTO {
   attachReceipt?: boolean;
 }
+
+export interface ISaleReceiptMailPresend {
+  tenantId: number;
+  saleReceiptId: number;
+  messageOptions: SaleReceiptMailOptsDTO;
+}
diff --git a/packages/server/src/loaders/eventEmitter.ts b/packages/server/src/loaders/eventEmitter.ts
index 5e052f376..5d3269646 100644
--- a/packages/server/src/loaders/eventEmitter.ts
+++ b/packages/server/src/loaders/eventEmitter.ts
@@ -85,6 +85,8 @@ import { BillTaxRateValidateSubscriber } from '@/services/TaxRates/subscribers/B
 import { WriteBillTaxTransactionsSubscriber } from '@/services/TaxRates/subscribers/WriteBillTaxTransactionsSubscriber';
 import { SyncItemTaxRateOnEditTaxSubscriber } from '@/services/TaxRates/SyncItemTaxRateOnEditTaxSubscriber';
 import { InvoiceChangeStatusOnMailSentSubscriber } from '@/services/Sales/Invoices/subscribers/InvoiceChangeStatusOnMailSentSubscriber';
+import { SaleReceiptMarkClosedOnMailSentSubcriber } from '@/services/Sales/Receipts/subscribers/SaleReceiptMarkClosedOnMailSentSubcriber';
+import { SaleEstimateMarkApprovedOnMailSent } from '@/services/Sales/Estimates/subscribers/SaleEstimateMarkApprovedOnMailSent';
 
 export default () => {
   return new EventPublisher();
@@ -105,8 +107,12 @@ export const susbcribers = () => {
     InventorySubscriber,
     CustomerWriteGLOpeningBalanceSubscriber,
     VendorsWriteGLOpeningSubscriber,
+
+    // # Estimate
     SaleEstimateAutoSerialSubscriber,
     SaleEstimateSmsNotificationSubscriber,
+    SaleEstimateMarkApprovedOnMailSent,
+
     ExpensesWriteGLSubscriber,
     SaleReceiptAutoSerialSubscriber,
     SaleInvoiceAutoIncrementSubscriber,
@@ -159,6 +165,7 @@ export const susbcribers = () => {
 
     // # Receipts
     SaleReceiptCostGLEntriesSubscriber,
+    SaleReceiptMarkClosedOnMailSentSubcriber,
 
     // Transaction locking.
     SalesTransactionLockingGuardSubscriber,
@@ -201,6 +208,6 @@ export const susbcribers = () => {
     BillTaxRateValidateSubscriber,
     WriteBillTaxTransactionsSubscriber,
 
-    SyncItemTaxRateOnEditTaxSubscriber
+    SyncItemTaxRateOnEditTaxSubscriber,
   ];
 };
diff --git a/packages/server/src/services/Accounts/AccountTransactionTransformer.ts b/packages/server/src/services/Accounts/AccountTransactionTransformer.ts
index 857fe5ccc..d0e3e487f 100644
--- a/packages/server/src/services/Accounts/AccountTransactionTransformer.ts
+++ b/packages/server/src/services/Accounts/AccountTransactionTransformer.ts
@@ -1,6 +1,5 @@
 import { IAccountTransaction } from '@/interfaces';
 import { Transformer } from '@/lib/Transformer/Transformer';
-import { transaction } from 'objection';
 
 export default class AccountTransactionTransformer extends Transformer {
   /**
diff --git a/packages/server/src/services/Accounts/AccountTransform.ts b/packages/server/src/services/Accounts/AccountTransform.ts
index 9297994be..98e19553e 100644
--- a/packages/server/src/services/Accounts/AccountTransform.ts
+++ b/packages/server/src/services/Accounts/AccountTransform.ts
@@ -34,7 +34,7 @@ export class AccountTransformer extends Transformer {
 
   /**
    * Retrieve formatted account amount.
-   * @param   {IAccount} invoice
+   * @param {IAccount} invoice
    * @returns {string}
    */
   protected formattedAmount = (account: IAccount): string => {
diff --git a/packages/server/src/services/Accounts/ActivateAccount.ts b/packages/server/src/services/Accounts/ActivateAccount.ts
index 1fcd104f6..26afd836d 100644
--- a/packages/server/src/services/Accounts/ActivateAccount.ts
+++ b/packages/server/src/services/Accounts/ActivateAccount.ts
@@ -5,7 +5,6 @@ import { IAccountEventActivatedPayload } from '@/interfaces';
 import events from '@/subscribers/events';
 import UnitOfWork from '@/services/UnitOfWork';
 import { EventPublisher } from '@/lib/EventPublisher/EventPublisher';
-import { CommandAccountValidators } from './CommandAccountValidators';
 
 @Service()
 export class ActivateAccount {
@@ -18,9 +17,6 @@ export class ActivateAccount {
   @Inject()
   private uow: UnitOfWork;
 
-  @Inject()
-  private validator: CommandAccountValidators;
-
   /**
    * Activates/Inactivates the given account.
    * @param {number} tenantId
diff --git a/packages/server/src/services/Sales/Estimates/SendSaleEstimateMail.ts b/packages/server/src/services/Sales/Estimates/SendSaleEstimateMail.ts
index 258496306..0ac580b90 100644
--- a/packages/server/src/services/Sales/Estimates/SendSaleEstimateMail.ts
+++ b/packages/server/src/services/Sales/Estimates/SendSaleEstimateMail.ts
@@ -8,11 +8,14 @@ import {
 import { SaleEstimatesPdf } from './SaleEstimatesPdf';
 import { GetSaleEstimate } from './GetSaleEstimate';
 import {
+  ISaleEstimateMailPresendEvent,
   SaleEstimateMailOptions,
   SaleEstimateMailOptionsDTO,
 } from '@/interfaces';
 import { ContactMailNotification } from '@/services/MailNotification/ContactMailNotification';
 import { parseAndValidateMailOptions } from '@/services/MailNotification/utils';
+import { EventPublisher } from '@/lib/EventPublisher/EventPublisher';
+import events from '@/subscribers/events';
 
 @Service()
 export class SendSaleEstimateMail {
@@ -31,6 +34,9 @@ export class SendSaleEstimateMail {
   @Inject('agenda')
   private agenda: any;
 
+  @Inject()
+  private eventPublisher: EventPublisher;
+
   /**
    * Triggers the reminder mail of the given sale estimate.
    * @param {number} tenantId -
@@ -49,6 +55,13 @@ export class SendSaleEstimateMail {
       messageOptions,
     };
     await this.agenda.now('sale-estimate-mail-send', payload);
+
+    // Triggers `onSaleEstimatePreMailSend` event.
+    await this.eventPublisher.emitAsync(events.saleEstimate.onPreMailSend, {
+      tenantId,
+      saleEstimateId,
+      messageOptions,
+    } as ISaleEstimateMailPresendEvent);
   }
 
   /**
@@ -99,7 +112,7 @@ export class SendSaleEstimateMail {
     return {
       ...mailOptions,
       data: formatterData,
-      attachEstimate: true
+      attachEstimate: true,
     };
   };
 
diff --git a/packages/server/src/services/Sales/Estimates/subscribers/SaleEstimateMarkApprovedOnMailSent.ts b/packages/server/src/services/Sales/Estimates/subscribers/SaleEstimateMarkApprovedOnMailSent.ts
new file mode 100644
index 000000000..99caa3952
--- /dev/null
+++ b/packages/server/src/services/Sales/Estimates/subscribers/SaleEstimateMarkApprovedOnMailSent.ts
@@ -0,0 +1,43 @@
+import { Inject, Service } from 'typedi';
+import events from '@/subscribers/events';
+import { ISaleEstimateMailPresendEvent } from '@/interfaces';
+import { DeliverSaleEstimate } from '../DeliverSaleEstimate';
+import { ServiceError } from '@/exceptions';
+import { ERRORS } from '../constants';
+
+@Service()
+export class SaleEstimateMarkApprovedOnMailSent {
+  @Inject()
+  private deliverEstimateService: DeliverSaleEstimate;
+
+  /**
+   * Attaches events.
+   */
+  public attach(bus) {
+    bus.subscribe(events.saleEstimate.onPreMailSend, this.markEstimateApproved);
+  }
+
+  /**
+   * Marks the given estimate approved on submitting mail.
+   * @param {ISaleEstimateMailPresendEvent}
+   */
+  private markEstimateApproved = async ({
+    tenantId,
+    saleEstimateId,
+  }: ISaleEstimateMailPresendEvent) => {
+    try {
+      await this.deliverEstimateService.deliverSaleEstimate(
+        tenantId,
+        saleEstimateId
+      );
+    } catch (error) {
+      if (
+        error instanceof ServiceError &&
+        error.errorType === ERRORS.SALE_ESTIMATE_ALREADY_DELIVERED
+      ) {
+      } else {
+        throw error;
+      }
+    }
+  };
+}
diff --git a/packages/server/src/services/Sales/PaymentReceives/PaymentReceiveMailNotification.ts b/packages/server/src/services/Sales/PaymentReceives/PaymentReceiveMailNotification.ts
index acb1ea7a1..bd8d4fa64 100644
--- a/packages/server/src/services/Sales/PaymentReceives/PaymentReceiveMailNotification.ts
+++ b/packages/server/src/services/Sales/PaymentReceives/PaymentReceiveMailNotification.ts
@@ -2,6 +2,7 @@ import { Inject, Service } from 'typedi';
 import {
   PaymentReceiveMailOpts,
   PaymentReceiveMailOptsDTO,
+  PaymentReceiveMailPresendEvent,
   SendInvoiceMailDTO,
 } from '@/interfaces';
 import Mail from '@/lib/Mail';
@@ -13,6 +14,8 @@ import {
 import { GetPaymentReceive } from './GetPaymentReceive';
 import { ContactMailNotification } from '@/services/MailNotification/ContactMailNotification';
 import { parseAndValidateMailOptions } from '@/services/MailNotification/utils';
+import { EventPublisher } from '@/lib/EventPublisher/EventPublisher';
+import events from '@/subscribers/events';
 
 @Service()
 export class SendPaymentReceiveMailNotification {
@@ -28,6 +31,9 @@ export class SendPaymentReceiveMailNotification {
   @Inject('agenda')
   private agenda: any;
 
+  @Inject()
+  private eventPublisher: EventPublisher;
+
   /**
    * Sends the mail of the given payment receive.
    * @param {number} tenantId
@@ -46,6 +52,13 @@ export class SendPaymentReceiveMailNotification {
       messageDTO,
     };
     await this.agenda.now('payment-receive-mail-send', payload);
+
+    // Triggers `onPaymentReceivePreMailSend` event.
+    await this.eventPublisher.emitAsync(events.paymentReceive.onPreMailSend, {
+      tenantId,
+      paymentReceiveId,
+      messageOptions: messageDTO,
+    } as PaymentReceiveMailPresendEvent);
   }
 
   /**
diff --git a/packages/server/src/services/Sales/Receipts/SaleReceiptMailNotification.ts b/packages/server/src/services/Sales/Receipts/SaleReceiptMailNotification.ts
index 572bed2f8..24add40cc 100644
--- a/packages/server/src/services/Sales/Receipts/SaleReceiptMailNotification.ts
+++ b/packages/server/src/services/Sales/Receipts/SaleReceiptMailNotification.ts
@@ -7,9 +7,15 @@ import {
   DEFAULT_RECEIPT_MAIL_CONTENT,
   DEFAULT_RECEIPT_MAIL_SUBJECT,
 } from './constants';
-import { SaleReceiptMailOpts, SaleReceiptMailOptsDTO } from '@/interfaces';
+import {
+  ISaleReceiptMailPresend,
+  SaleReceiptMailOpts,
+  SaleReceiptMailOptsDTO,
+} from '@/interfaces';
 import { ContactMailNotification } from '@/services/MailNotification/ContactMailNotification';
 import { parseAndValidateMailOptions } from '@/services/MailNotification/utils';
+import { EventPublisher } from '@/lib/EventPublisher/EventPublisher';
+import events from '@/subscribers/events';
 
 @Service()
 export class SaleReceiptMailNotification {
@@ -25,6 +31,9 @@ export class SaleReceiptMailNotification {
   @Inject()
   private contactMailNotification: ContactMailNotification;
 
+  @Inject()
+  private eventPublisher: EventPublisher;
+
   @Inject('agenda')
   private agenda: any;
 
@@ -37,14 +46,21 @@ export class SaleReceiptMailNotification {
   public async triggerMail(
     tenantId: number,
     saleReceiptId: number,
-    messageOpts: SaleReceiptMailOptsDTO
+    messageOptions: SaleReceiptMailOptsDTO
   ) {
     const payload = {
       tenantId,
       saleReceiptId,
-      messageOpts,
+      messageOpts: messageOptions,
     };
     await this.agenda.now('sale-receipt-mail-send', payload);
+
+    // Triggers the event `onSaleReceiptPreMailSend`.
+    await this.eventPublisher.emitAsync(events.saleReceipt.onPreMailSend, {
+      tenantId,
+      saleReceiptId,
+      messageOptions,
+    } as ISaleReceiptMailPresend);
   }
 
   /**
diff --git a/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptCostGLEntriesSubscriber.ts b/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptCostGLEntriesSubscriber.ts
index 5e6311005..39590198b 100644
--- a/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptCostGLEntriesSubscriber.ts
+++ b/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptCostGLEntriesSubscriber.ts
@@ -6,7 +6,7 @@ import { SaleReceiptCostGLEntries } from '../SaleReceiptCostGLEntries';
 @Service()
 export class SaleReceiptCostGLEntriesSubscriber {
   @Inject()
-  saleReceiptCostEntries: SaleReceiptCostGLEntries;
+  private saleReceiptCostEntries: SaleReceiptCostGLEntries;
 
   /**
    * Attaches events.
diff --git a/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptMarkClosedOnMailSentSubcriber.ts b/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptMarkClosedOnMailSentSubcriber.ts
new file mode 100644
index 000000000..3a8d26394
--- /dev/null
+++ b/packages/server/src/services/Sales/Receipts/subscribers/SaleReceiptMarkClosedOnMailSentSubcriber.ts
@@ -0,0 +1,41 @@
+import { ISaleReceiptMailPresend } from '@/interfaces';
+import events from '@/subscribers/events';
+import { CloseSaleReceipt } from '../CloseSaleReceipt';
+import { Inject, Service } from 'typedi';
+import { ServiceError } from '@/exceptions';
+import { ERRORS } from '../constants';
+
+@Service()
+export class SaleReceiptMarkClosedOnMailSentSubcriber {
+  @Inject()
+  private closeReceiptService: CloseSaleReceipt;
+
+  /**
+   * Attaches events.
+   */
+  public attach(bus) {
+    bus.subscribe(events.saleReceipt.onPreMailSend, this.markReceiptClosed);
+  }
+
+  /**
+   * Marks the sale receipt closed on submitting mail.
+   * @param {ISaleReceiptMailPresend}
+   */
+  private markReceiptClosed = async ({
+    tenantId,
+    saleReceiptId,
+    messageOptions,
+  }: ISaleReceiptMailPresend) => {
+    try {
+      await this.closeReceiptService.closeSaleReceipt(tenantId, saleReceiptId);
+    } catch (error) {
+      if (
+        error instanceof ServiceError &&
+        error.errorType === ERRORS.SALE_RECEIPT_IS_ALREADY_CLOSED
+      ) {
+      } else {
+        throw error;
+      }
+    }
+  };
+}
diff --git a/packages/server/src/subscribers/events.ts b/packages/server/src/subscribers/events.ts
index a46c32696..882027f98 100644
--- a/packages/server/src/subscribers/events.ts
+++ b/packages/server/src/subscribers/events.ts
@@ -172,6 +172,10 @@ export default {
     onRejected: 'onSaleEstimateRejected',
 
     onNotifyMail: 'onSaleEstimateNotifyMail',
+
+    onPreMailSend: 'onSaleEstimatePreMailSend',
+    onMailSend: 'onSaleEstimateMailSend',
+    onMailSent: 'onSaleEstimateMailSend',
   },
 
   /**
@@ -195,6 +199,10 @@ export default {
 
     onNotifySms: 'onSaleReceiptNotifySms',
     onNotifiedSms: 'onSaleReceiptNotifiedSms',
+
+    onPreMailSend: 'onSaleReceiptPreMailSend',
+    onMailSend: 'onSaleReceiptMailSend',
+    onMailSent: 'onSaleReceiptMailSent', 
   },
 
   /**
@@ -215,6 +223,10 @@ export default {
 
     onNotifySms: 'onPaymentReceiveNotifySms',
     onNotifiedSms: 'onPaymentReceiveNotifiedSms',
+
+    onPreMailSend: 'onPaymentReceivePreMailSend',
+    onMailSend: 'onPaymentReceiveMailSend',
+    onMailSent: 'onPaymentReceiveMailSent', 
   },
 
   /**