A proforma invoice is a preliminary bill or estimated invoice which is used to request payment from the committed buyer for goods or services before they are supplied. A proforma invoice includes a description of the goods, the total payable amount, and other details about the transaction.
In myBooks, you can create a proforma invoice before creating the Invoice for the customer confirmation.
To enable the Proforma Invoice, Goto Settings > Business Settings > Preferences > Proforma Invoice
Transactions > Proforma Invoice, Proforma Invoice list page opens
Then Click on Create Proforma Invoice, then select the contact
Enter the particulars of the proforma invoice, then click on Save.