Purchase Order
A formal document issued by a buyer that authorizes the acquisition of specified goods or services from a supplier at agreed terms and price.
A purchase order is an official commercial document generated by an organisation's procurement or finance function that instructs a supplier to provide specific goods or services at a stated price and on defined terms. In travel and expense management, acquisition orders are used for high-value, pre-approved supplier engagements — technology contracts, event management services, hotel allotment agreements — where the organisation needs a formal authorization record before the supplier begins work or before invoices can be processed.
Why it matters
Acquisition orders create the authorization baseline against which supplier invoices are matched before payment is released. Without a PO, invoice matching is impossible — finance cannot confirm that the service was formally authorised before it was rendered. In travel programmes, this matters most for direct-billed services: hotel master accounts, TMC management fees, event venue invoices, and technology platform charges all benefit from PO authorization to ensure that charges can be verified before payment and that budget holders have formally committed to the spend.
How it works in practice
A purchase order is raised in the company's procurement or finance system by an authorised budget holder, specifying the supplier, the goods or services, the price, the delivery timeline, and the cost center to be charged. The PO number is communicated to the supplier, who references it on all invoices. AP uses the PO number to perform a three-way match — PO, invoice, and delivery confirmation — before authorizing payment. POs also create a commitment record in the budget system, reserving the budgeted amount before the invoice arrives.
The takeaway
Establish a PO requirement for all direct-billed travel supplier contracts above a defined threshold. The discipline of requiring a PO before supplier services begin prevents unauthorized spend, guarantees budget availability is confirmed upfront, and provides the authorization reference needed to process invoices efficiently. Travel programmes that operate without POs on direct-billed suppliers routinely face invoice disputes and payment delays that damage supplier relationships.