A Purchase Requisition
A purchase requisition defines the internal requirement for a
material or a service.
A Purchase Order
A purchase order is a contractual request to a vendor to supply
given goods or services according to the agreed conditions.
A funds reservation is a manual commitment which you can use to
reserve funds for costs you are fairly certain to incur, but you
cannot yet assign to a specific business transaction (such as, a
purchase order or a material reservation).
These different forms of funds commitments are also referred to
as commitment categories. For example, purchase order
commitments or purchase requisition commitments.
Provisional and Firm Funds
We can also differentiate between
provisional and firm funds commitments:
Provisional commitments, such as purchase requisitions, have a
control function and can be changed at any time.
Firm commitments, such as purchase orders, are based on
contractual obligations. The parties to the agreements cannot make
any short-term, unilateral changes to the commitments.