Can computers automate accounting?

I assume you want to ensure that A/P is processing only what you authorized to be paid on the invoices. You could set up a spreadsheet and enter the bills before you hand them over to A/P for processing. You could ask A/P to generate a payables report based on your g/l code and compare it with your spreadsheet before they cut checks. However, you are creating unnecessary work for all if your A/P dept. is competent and follows internal controls. Just indicate what you want paid on the invoice by highlighting it or red-lining an amount and let A/P take care of it. Have an admin. make copies and file them before they are sent to A/P.

Quick & dirty might be a pen & paper log sheet. Guess it depends on what kind of volume you're looking at.

Not sure from your post what you might want a computer to do - other than the suggested spreadsheet. There's not going to be a substitute for a human being looking at the invoices to make sure they are accurate.