A purchase order (PO) is a document issued by a buyer to a seller, indicating the type, quantity, and agreed-upon price for goods or services the seller will provide to the buyer. It is used to control the purchasing of products such as spare parts for maintenance. Purchase orders are typically used in business-to-business transactions between a buyer and a supplier. They are also used to track orders, ensure accurate record-keeping, and provide a legal document for both parties. Purchase orders are typically created by the buyer and sent to the seller, who then confirms the order and sends an invoice for payment. Many CMMS systems have features that allow maintenance managers and other users to create purchase orders for needed parts and materials need for equipment maintenance.