1.  From Accounts Payable select Mail and select Forms.
2.  Highlight Purchase Order Forms, click on New.
3.  Select the Format tab and highlight Detail.
4.  Mark the 'Bill to' address box, and select the address from the drop-down.
5.  Save the form and give it a name.

The addresses in this field are stored in AP, Configuration, Addresses, and can be added here also.

If you want your PO's to have different billing addresses, you will need to process the PO's in separate parameters.

You can Preview the PO's to see how they will look when printed.