A Supplier Purchase Order (PO) is a formal document issued by a buyer to a seller, instructing the seller to deliver goods or services at specified prices and terms of payment. The PO is legally binding on both parties, specifying what must be provided, who will provide it, when it must be delivered, and how it is to be paid for. It also serves as an official record of the transaction, including itemized costs and payment instructions. A PO serves as the primary source of information throughout the supply chain process and helps ensure accuracy with respect to product specifications, delivery schedules, and payment terms.