A purchase order is a written authorization from a buyer to acquire goods or services. The document authorizes a supplier to deliver to the buyer at the price, quality level, delivery date, and certain other terms specified in the agreement. A purchase order is legally binding after the supplier counter-signs it.
A purchase order is time-consuming to create. To reduce the workload, some organizations issue a master purchase order to each supplier, authorizing considerably more than is initially needed, and then issue releases against the master purchase order, as needed. To save time, many purchase orders are now delivered in electronic format over the Internet.