Recording receipt against Export Invoice is same as recording receipt against normal invoice. Let's see how to record such receipts:
Go to Income > Receipts > New Receipt
Select tab Receive Money. Fill up the fields as follows:
Money Received from: Select the customer from the drop down from whom has the payment is received.
Receive date: Enter the date on which the payment is received.
Deposit to Account: Select the account from the drop down.
Receipt Mode: Enter the receipt mode - Cash/ Cheque/ Credit or Debit card / Internet Banking
Description: Can mention any information relevant.
Click on save and its done.
Your receipt against the Invoice is saved. You can edit and print the same.
Another way to save the receipts on export Invoice is click on the invoice against which you have received payment:
Click on "Add payment"
Fill all the details with the details of exchange rate as show in above screenshot.
Click on save and its done.