For companies that get a lot of invoices, the workflow we proposed in "The Importance of Processing an Invoice the Moment You Get It," which requires employees to confirm each and every invoice they are in charge of, isn't really practical. In this case you'll want to let accounting process some of the less important invoices, like power bills and yearly contract renewals, themselves.
This sample separates inputting and processing steps; in other words, it requires that each invoice be registered and processed by two separate people. This eliminates mistakes and violations.
On a side note, the amount and content of invoices you receive are usually predictable. Once you get used to handling workflows, you may want to be able to input order info into the invoice workflow beforehand, or even automatically start the invoice workflow from a procurement or ringi processes. But maybe we should stick to one of BPM's basic rules: avoid excessively complicated stuff.