There is another way, under the "+" sign, where you can add transactions etc., under VENDORS, you will see "Create Vendor Credit".  This is the easiest way, but it might depend on what version you have, #1. And #2, if you use a vendor credit, you should always make sure to either auto-apply so just remember you have a credit to apply when you pay the vendor's bills, because it is not in all versions that it show you have an available credit to use.