An accounts payable process flow is easy to draw and hard to draw honestly. The version that ends up in a procedure document runs left to right: invoice in, coded, matched, approved, posted, paid. The version that runs in the building has loops in it. The invoice goes back because it was coded wrong. It waits because the approver is away. It returns from matching because the order was for a different quantity. Those loops are the process, in the sense that they are where the hours are, and a diagram without them describes a business nobody works in. This page is about drawing the flow with its loops, and using the drawing to find the two or three worth removing.
Draw the loops, because the loops are the cost
Every arrow that goes backwards is rework, and rework is where a payables function spends the part of its month it cannot account for. Ask the person who processes invoices where things come back from, and draw those arrows first. The forward path is the easy half and everybody already agrees on it.
Put a count on each loop
A loop that catches 2% of invoices and one that catches 30% are different problems, and only counting tells you which is which. On the worked example on this site, 400 invoices at three touches of six minutes with a 12% exception rate is 134.4 hours a month, $4,300.80 at a $32 loaded rate and $10.75 an invoice. The loops are inside that number and each one is worth its own share of it.
Remove the loop, not the step
The instinct is to speed the steps up. The saving is in stopping the invoice going backwards: capture the fields so coding is right first time, publish the approver map so nothing waits on a guess, and fix the tolerances so trivial differences stop returning.
Questions people ask about accounts payable process flow
What is the difference between a process flow and a workflow?
In everyday use, none. Where the distinction is useful: the flow is the picture and the workflow is the thing running. A picture that does not match the thing running is the commonest problem with both.
Who should draw it?
The person who processes the invoices, with finance holding the pen. Diagrams drawn by managers describe the intended process, which is exactly the version that already exists in the procedure nobody reads.
How detailed should it be?
One page. If it does not fit on one page it is describing several processes, and separating them by spend category is usually more revealing than adding detail.