What is Purchase Order (PO)?

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A purchase order (PO) is a formal document issued by a buyer that specifies products or services, quantities, prices, delivery details, and commercial terms. In B2B ecommerce, PO numbers and approval rules are often part of checkout and order management.

A PO is usually generated after the buyer’s internal requisition and approval process. It identifies the buyer and supplier, products or services, quantities, agreed prices, delivery details, and a purchase-order number used for tracking and invoicing. In many B2B relationships, the PO is the commercial document that authorizes the supplier to fulfill the order.

In ecommerce, PO handling can include:

• Allowing an approved buyer to enter a PO number during checkout.

• Receiving a complete electronic purchase order through cXML, EDI, or API integration.

• Validating contract prices, ship-to addresses, credit, product eligibility, and other account rules.

• Passing the PO reference into ERP, fulfillment, invoice, and customer-service records.

A PO number by itself is not the same as an integrated purchase order. Some stores simply capture the reference, while mature B2B integrations receive structured PO data automatically. The right model depends on the buyer’s procurement process and how much manual work the supplier wants to eliminate.

Example: A buyer’s approved requisition becomes PO 45001234, which is transmitted to the supplier and then preserved through ERP order creation, shipment, invoice, and reconciliation.