Choosing software for purchase order work usually starts with the document and should start with the data. Producing a tidy order to email a supplier is table stakes and every product does it. What separates useful products is whether they keep three quantities against every line as reality unfolds, because that is what makes matching, accruals and delivery chasing possible without manual reconstruction.
Three quantities per line
Ordered, received and invoiced. They diverge legitimately and constantly: partial deliveries, over-shipments, several invoices against one line. Software that holds only a document total cannot tell you whether you are being billed for goods that never arrived, which is precisely the question the three-way match exists to answer.
Revisions kept rather than overwritten
Prices change, quantities are amended, dates slip. Each amendment should be a dated revision so you can see what was agreed when. Overwriting is convenient at the time and expensive in a supplier disagreement, where the whole question is what the order said on a particular date.
An open-order view anyone can run
What is ordered but not received, and what is received but not invoiced. The first is a chase list, the second is your accrual. Both should be available without exporting to a spreadsheet and rebuilding them, and if they are not, somebody is doing that work by hand every month.
Questions people ask about software for purchase order
Is our accounting system enough?
Sometimes. Check specifically whether it records receipts at line level and keeps revisions, since those are the common gaps rather than the ordering itself.
What about service purchases with no delivery?
They are usually matched two-way against the order, with a separate confirmation that the work was done. Make sure the software can express that rather than demanding a goods receipt.
How important is supplier acknowledgement?
Useful, not essential. Knowing a supplier has seen the order removes a class of dispute, but it matters far less than tracking what actually arrives.