A preliminary bill of sale sent to buyers in advance of a shipment or delivery of goods. Typically, it gives a description of the purchased items, notes the cost, as well as other important information like shipping weight and transport charges. Pro forma invoices are often used for customs purposes on imports.
A pro forma invoice differs from a simple price quotation in that it is usually considered a binding agreement, despite the fact that, like a price quote, the terms of sale are subject to change. Pro forma invoices are used by a wide variety of businesses in virtually all industries.
Investment dictionary. Academic. 2012.