Certification of Payment (COP) is a document that is certified by project managers that instructs their internal finance department to pay an amount to another organization for services provided or material delivered. After a tender is won by a vendor, a PO (purchase order) is issued by the client (internal organization) to complete certain works or deliver some material. When this is completed, the vendor will generate an invoice which is handed over to the Quantity surveyor on the client side. The Quantity surveyor will create a COP based on the invoice and get it reviewed by the project manager who will then send it to the project head for approval. Once approved, the COP is sent to the finance department for the release of the specified amount.

---