diff --git a/schemas/app/inventory/Point of Sale/POSSettings.json b/schemas/app/inventory/Point of Sale/POSSettings.json
index efb8d70a0..a51ec0ccf 100644
--- a/schemas/app/inventory/Point of Sale/POSSettings.json	
+++ b/schemas/app/inventory/Point of Sale/POSSettings.json	
@@ -51,7 +51,7 @@
       "section": "Default"
     },
     {
-      "fieldname": " ",
+      "fieldname": "submitInvoice",
       "label": "Post Payment",
       "fieldtype": "Check",
       "default": false,
diff --git a/src/pages/POS/POS.vue b/src/pages/POS/POS.vue
index 7e78859e2..81584f51c 100644
--- a/src/pages/POS/POS.vue
+++ b/src/pages/POS/POS.vue
@@ -138,6 +138,7 @@ import {
   ItemQtyMap,
   ItemSerialNumbers,
 } from 'src/components/POS/types';
+import { ValidationError } from 'fyo/utils/errors';
 
 const COMPONENT_NAME = 'POS';
 
@@ -477,19 +478,25 @@ export default defineComponent({
     },
 
     async addItem(item: POSItem | Item | undefined) {
-      await this.sinvDoc.runFormulas();
+      try {
+        if (this.sinvDoc.isSubmitted) {
+          throw new ValidationError(
+            t`Cannot add an item to a submitted invoice.`
+          );
+        }
 
-      if (!item) {
-        return;
-      }
+        await this.sinvDoc.runFormulas();
 
-      const existingItems =
-        this.sinvDoc.items?.filter(
-          (invoiceItem) =>
-            invoiceItem.item === item.name && !invoiceItem.isFreeItem
-        ) ?? [];
+        if (!item) {
+          return;
+        }
+
+        const existingItems =
+          this.sinvDoc.items?.filter(
+            (invoiceItem) =>
+              invoiceItem.item === item.name && !invoiceItem.isFreeItem
+          ) ?? [];
 
-      try {
         if (item.hasBatch) {
           for (const invItem of existingItems) {
             const itemQty = invItem.quantity ?? 0;
diff --git a/src/pages/POS/SavedInvoiceModal.vue b/src/pages/POS/SavedInvoiceModal.vue
index 5cf573eab..3db5f3f99 100644
--- a/src/pages/POS/SavedInvoiceModal.vue
+++ b/src/pages/POS/SavedInvoiceModal.vue
@@ -8,7 +8,7 @@
       <Button
         :background="false"
         class="w-full h-full p-2 mt-2"
-        :class="{ 'dark:bg-gray-890': savedInvoiceList }"
+        :class="{ 'dark:bg-gray-890 underline': savedInvoiceList }"
         @click="savedInvoiceList = true"
         >Saved</Button
       >
@@ -16,7 +16,7 @@
       <Button
         :background="false"
         class="w-full h-full p-2 mt-2"
-        :class="{ 'dark:bg-gray-890': !savedInvoiceList }"
+        :class="{ 'dark:bg-gray-890 underline': !savedInvoiceList }"
         @click="savedInvoiceList = false"
         >Submitted</Button
       >