There is no function to display a due date on accounts.

 

However, you can use the discount function to achieve the same effect. Apply a discount on the Fee page and adjust the message to include the date that the discount expires. That way the discounted fee will appear next to the normal fee, and the date that the discount expires will be shown.

 

Alternatively, you could put a message on the bottom row of the Items page, although the due date would have to be specifically inserted into each account.