Instead of only putting the words, "You paid $450" when nobody knows who "you" is, you can also use my name and the name of my business on the receipt. That way, when I turn it in for re-imbursement, the entity who gets the invoice from me really knows it was me who paid. Instead of assuming the last four digits of the credit card are my credit card, which currently is the ONLY information that can identify me as the payor.