The term purchase order (PO) is a purchaser’s authorization in order to formalize the purchase to a seller. The purchase order would indicate the type, quantities, and price for the products or services which the seller has agreed upon with the purchaser. There are three types of purchase orders. The first type is a regular purchase order, which is used for a one time purchase. The second type is a standing purchase order which is for goods or services needed from a supplier on a regular basis. The third type is the blanket purchase order, which is a long-term agreement.