What is a po number on an invoice?

A PO number on an invoice refers to a purchase order number. A purchase order is a document issued by a buyer or purchaser to a vendor or supplier that outlines the details of a purchase, including the type of goods or services being purchased, the price, delivery dates, and terms of payment. The PO number is a unique identifier assigned to each purchase order and is used to track the transaction throughout the purchasing process. The PO number is typically included on an invoice to ensure accurate billing and payment of the purchased goods or services.