A Requisition Number is an official business term used to refer to a unique number assigned to a specific purchase order or request. It is typically used to track the progress of the order or request, as well as to identify it for future reference. The number is typically assigned by the company or organization that is making the purchase or request, and is used to help ensure that the order or request is properly tracked and fulfilled. Requisition Numbers are also used to help prevent duplicate orders or requests, as well as to help ensure that the correct items are ordered or requested. In addition, Requisition Numbers can be used to help identify any changes or updates that have been made to the order or request.