A proforma invoice is a document you send to a buyer before the actual sale happens. It shows what you plan to supply, at what price, and under what terms. It is not a tax invoice. It does not create a GST liability. The buyer cannot use it to claim input tax credit. Think of it as a formal quotation in invoice format, sent before the deal is confirmed. If you want to create a proforma invoice that automatically converts to a GST tax invoice once the order is confirmed, that part of the process