An Invoice Purchase Order (PO) is an official document created by a seller that confirms the sale of products or services to a buyer. It details the price, quantity, and terms of the transaction, and is used as a proof of purchase when accepting payment from buyers. With the PO, buyers can ensure they are getting accurate pricing and quality goods. It also protects them if something goes wrong with the transaction. Having an Invoice Purchase Order in place helps businesses streamline their purchasing processes and keeps things organized for both parties involved.