You can leave entry instructions for the AP Capture Team on the Vendor record. When a new AP Invoice is created for that Vendor, the instructions will appear for the User. 

To leave instructions for the AP Capture Team, navigate to the desired Vendor record and open the 'Vendor Additional Info' tab. In the 'Entry Instructions' field, enter the details that you want to communicate with the AP Capture Team and then save the record.

These instructions will then be listed for this Vendor on each new AP Invoice form as they are being entered in R365.