I can help provide some information about adding fields to the vendor bill.
Currently, this isn't available if you're using the QuickBooks Pro or Premier version. However, if you're using QuickBooks Enterprise, you'll be able to do this with just a few clicks.
When you enter a bill, you can right click on the column and select Customize Columns. You can add a field by selecting the Available Columns, however, you can't remove the Chosen Columns since this is a default field in the bill.