We apologize that the feature you’re looking for isn’t available right now, but we suggest you record the advance payment from the customer ledger. Once you convert the proforma invoice into a sales invoice, you can settle the invoice through the advance.
Please follow the below mentioned process to record advance payment.
Kindly go to the customer >> click on the more option >> click on you got >> enter the amount >> select the payment type >> click on add Payment.
Link: Swipe