It would be handy to have the ability of adding a recurring note such as a clause for payment terms to the bottom of all invoices ie. "Overdue accounts with incur xx surcharge". Or a "remember this" checkbox on the invoice note so it doesn't need to be added every time. If not, an option for a custom note to be saved in the drop-down list would help.
'Invoice recurring note or "remember this" checkbox for note to customer"