How to do a purchase order from the approved request to the sent document, including the two terms almost every hand-written order omits. The mechanics are quick. What matters is the order of operations, because applying tax before the discount overstates the bill, and starting from a blank sheet rather than from the approved request is how the order stops matching what anybody agreed to.
Start from the approved request, not from a blank sheet
If a requisition was raised and approved, the order should be built from it rather than typed afresh. Re-keying is where the quantity, the price and the number drift apart, and it is the single commonest way a purchase order stops matching the thing that was actually approved.
Take the next number and never reuse one
Sequential is fine and simple beats clever. On the worked example the next number is 1042 and the one after is 1043. The only two rules that matter are that a number is never reused, even for a corrected order, and that it appears on the document the supplier receives so it comes back on the invoice.
Price it in the right order: discount, then tax, then shipping
40 units at $18.50 is $740; a 5% discount takes $37 off to leave $703; tax at 7% on that is $49.21; and $75 of shipping brings it to $827.21. Applying tax before the discount overstates it, which is the commonest arithmetic error on a hand-built order and grows with the size of the order.
State the two terms everyone omits
When you need it, and when you will pay. Both are single lines and both are left off most hand-written orders. They are also the two that decide whether a late delivery or an early demand for payment is a misunderstanding or a departure from something you both agreed to.
Questions people ask about how to do a purchase order
How do I create a purchase order?
Start from the approved request, take the next number in your sequence, price the lines with the discount applied before tax, add shipping, and state the delivery date and payment terms.
Can I just send an email?
Yes, if it carries the same fields and a number. The document format is a convenience; the number and the stated terms are the substance.
What number should the first order be?
Anything that will not repeat. Starting at 1001 rather than 1 is a common convention and makes an early order look less like a first attempt, which occasionally matters with a new supplier.