A purchase requisition is an internal document in which somebody asks permission to buy something, before any supplier has been contacted and before any commitment exists. It is easy to confuse with a purchase order, and the difference matters because the two are approved by different people at different moments, and reversing that order removes the control entirely.
What goes on one
The requester and their department, what is wanted and how much, an estimated cost, the cost centre or budget it comes from, when it is needed, and why. Five fields plus the requester. Keeping it short matters more than completeness, because a long form is the most reliable way to make people stop raising requisitions at all.
Who approves it, and against what
A budget holder, against a threshold taken from your existing delegated authority. The question being answered is whether the organisation should spend this money, which is different from whether the price is right or whether the eventual invoice is correct. Those two are answered later by purchasing and by payables respectively.
What happens to it afterwards
An approved requisition becomes a purchase order raised by whoever handles buying, carrying its approval forward. It does not disappear: it is the record of who asked and who agreed, and it should stay linked to the order and, later, to the invoice that matches against it, so the whole chain is traceable.
Questions people ask about what is a purchase requisition
Is a requisition binding?
No. It is internal and commits nobody outside the organisation. The commitment is made by the purchase order or a contract.
Who raises one?
Whoever needs the goods or service, usually outside finance, which is why the form has to be short and the answer quick.
Do small purchases need one?
Most organisations set a threshold. Setting it deliberately beats letting people guess, which produces inconsistent practice.
How quickly should one be answered?
Same working day for routine requests. Anything slower competes badly with a company card, and requests that lose that competition become invoices with no order behind them, which is the expensive path.
What makes people stop using requisitions?
Delay and silence. A request answered in a week, or one that vanishes without acknowledgement, teaches somebody to buy another way, and that lesson lasts far longer than the single slow approval that caused it.