Add optional statuses back

docs/anchoring-assets/anchor-platform/sep24-user-guide.mdx

@@ -529,6 +529,14 @@ When KYC process is long (for example, ID verification), it's advised to first s
 
 ##### Processing KYC Information
 
+:::tip
+
+This step is optional. Most business don't use it: you can skip it and go to the [next one](#ready-to-receive-funds)
+
+Using this status is encouraged when KYC verification may need to be performed asynchronously.
+
+:::
+
 Update for this action is simply changing transaction status. It's a good idea to modify message too, reflecting details of the process:
 
 <CodeExample>
@@ -595,6 +603,33 @@ Asset field is optional. When not set, it defaults to the asset user requested.
 
 :::
 
+##### Waiting For User Funds
+
+:::tip
+
+This step is optional. Most business don't use it: you can skip it and go to the [next one](#sending-stellar-transaction)
+
+You should only use this status if the off-chain payment method being used notifies you of a pending inbound payment.
+
+:::
+
+After update in the previous chapter has been made, user will be notified that your service is ready to receive funds. In real world, transfer confirmation may take time. In such cases, transaction should be set to a new status, after funds have been received, but not confirmed yet.
+
+<CodeExample>
+
+```json
+{
+  "transaction": {
+    "id": "<transaction_id>",
+    "status": "pending_external",
+    "external_transaction_id": "<id_of_external_transaction>",
+    "message": "Transfer is being verified"
+  }
+}
+```
+
+</CodeExample>
+
 ##### Sending Stellar Transaction
 
 The next step would be sending Stellar transaction. First, let's change status to reflect the latest transaction state: