Define pro forma invoices and their Uses?

A proforma invoice is a document presented by seller to the buyer to notified them regarding the price of a specific services or product, therefore it is considered as temporary invoice or not rue invoice.

If you need to issue a sales document for goods or services you haven't supplied yet, you can issue a proforma invoice to offer goods or services to customers. Proforma invoices are also often used to declare the value of goods for customs.