The purchasing process encompasses all of the procedures that you will follow from first requesting goods to receiving items delivered to you by a supplier.
Requisitions are documents used to request purchases.
Some organizations call requisitions purchase authorizations. Once you have created a requisition, you must submit the requisition that becomes subject to the approval process. The supplier acknowledges receipt of the purchase order and sends a message, called a PO Acknowledgment, to your organization. Upon receipt of the items you record the receipt of the goods in the Purchasing Application program. The supplier sends your organization an invoice via the Internet.