What is Purchase Requisition vs Purchase Order?

**A purchase requisition and a purchase order (PO) are two distinct documents in the procurement process that are often confused but serve fundamentally different roles.** A purchase requisition is an internal document submitted by an employee or department to request authorization to purchase goods or services. It is the first step in the procurement workflow and remains internal to the buying organization. A purchase order, by contrast, is the formal external document sent to the vendor to authorize and initiate the purchase after the requisition has been approved. The distinction matters because the purchase requisition is a request for internal approval -- it has no legal standing with the vendor and does not obligate the company to buy anything. The purchase order, once accepted by the vendor, creates a contractual commitment between buyer and seller. Many organizations require employees to submit a requisition, have it approved by a manager or finance team, and only then issue a PO to the selected vendor. For freelancers and vendors who serve corporate clients, understanding this two-step process explains why there can be a delay between a project manager saying "yes, we want to hire you" and the purchase order actually arriving. The PO cannot be issued until the requisition clears the internal approval chain.

The procurement workflow in most medium and large organizations follows a defined sequence. It begins when an employee identifies a need and submits a purchase requisition to the purchasing or finance department. The requisition includes a description of the goods or services needed, estimated cost, preferred vendor if known, business justification, and desired delivery timeline. The requisition is reviewed by an approving manager and often a budget owner. If the spend fits within the budget and the business justification is accepted, the requisition is approved and converted into a purchase order. The purchasing department creates the PO with formal terms -- vendor details, line items, pricing, payment terms, and delivery requirements -- and sends it to the vendor. The vendor acknowledges the PO (sometimes called a PO acknowledgment or order confirmation), performs the work or delivers the goods, and sends an invoice referencing the PO number. The buyer's AP team matches the invoice to the PO and receiving documents, then releases payment. This entire sequence -- from requisition to payment -- can take anywhere from days to weeks in large organizations.

Freelancers cannot see the internal requisition process happening at a client's organization, but they experience its effects when there are unexpected delays between a verbal agreement to proceed and the arrival of a formal purchase order. Understanding that PO delays are almost always caused by internal approval processes -- not client disinterest -- helps freelancers manage expectations and follow up appropriately. When a project contact says the PO is coming but it has not arrived after several days, it is appropriate to follow up with a polite inquiry: "Could you share the status of the purchase order? I want to make sure I can schedule your project as soon as authorization is in place." This is professional and often triggers the contact to check on the internal approval status. Freelancers should never begin substantial billable work while waiting for a PO in a PO-required environment. If a client's procurement rules require a PO before payment, working without one risks having your invoice delayed or disputed because the work was not pre-authorized. If you must begin work before the PO arrives -- due to tight deadlines -- get written confirmation from the client's authorized contact that the work is approved and the PO is forthcoming.

The three documents represent sequential stages in a complete procurement transaction. A purchase requisition is internal and precedes any commitment to a vendor. A purchase order is external and creates a commitment to the vendor. An invoice is the vendor's payment request after the work is complete. From a freelancer's perspective, you will only ever see the PO and invoice stages. The requisition is invisible to you -- it happens entirely within the client's organization before you are contacted. But knowing that the requisition must be approved before the PO can be issued helps you understand why PO timing is not always within your direct client contact's control. For accounting purposes: purchase requisitions are internal controls; purchase orders are commitments (often logged as purchase commitments in the buyer's financial system); and invoices are accounts payable liabilities once received and approved.

Practical steps for freelancers navigating corporate procurement: 1. Ask about procurement requirements on the first call -- Before any proposal, ask whether the company uses a PO system and what the typical timeline is from request to PO issuance. 2. Build PO lead time into your project schedule -- If the client needs three to five business days to process a requisition and issue a PO, account for this in your project start date. 3. Request the PO number in your proposal acceptance or statement of work -- When a client accepts your proposal, include a line requesting the PO number before work begins. 4. Follow up proactively on outstanding POs -- If a PO has not arrived within the expected timeframe, contact your project manager to check on the status. 5. Keep copies of all POs -- File each PO with the associated project for easy reference when invoicing.

Eonebill.ai streamlines the invoicing side of PO-based procurement workflows. When you receive a purchase order from a corporate client, you can create a matching invoice in Eonebill's [free invoice generator](/free-tools/invoice-generator) that references the PO number, mirrors the line items and pricing from the PO, and includes the correct payment terms -- making it easy for the client's AP team to match and approve your invoice quickly. Eonebill Pro and Business plans at [Eonebill pricing](/pricing) let you store PO references against open invoices so you can track which corporate invoices are linked to approved purchase orders and which are waiting for PO issuance.

1. Assuming a verbal go-ahead equals a PO: A project manager saying "yes, let us proceed" is not the same as an approved purchase order. In PO-required environments, work only on projects with issued POs. 2. Not asking about the PO process early enough: Discovering that a client requires a PO after you have already started work is stressful. Ask at the proposal stage. 3. Losing track of PO expiration dates: Some purchase orders have expiration dates. Work and invoicing must be completed within the PO validity period or a new PO must be issued. 4. Submitting invoices before POs are issued: In strict procurement environments, invoices submitted without a corresponding PO are automatically rejected regardless of whether the work was completed. 5. Not following up on POs stuck in internal approval: If a requisition is stalled in the approval chain, the delay directly affects your ability to start and bill for work. Proactive follow-up with your client contact is appropriate and expected.

[Purchase order vs invoice](/glossary/purchase-order-vs-invoice) explores the relationship between POs and vendor invoices in detail. [Accounts payable](/glossary/accounts-payable) is the buyer-side function that processes both purchase orders and vendor invoices. [Invoice](/glossary/invoice) is the payment request issued by the vendor after fulfilling the purchase order. [Payment terms](/glossary/payment-terms) are typically defined in the purchase order and govern when the vendor invoice is due.