If we email our customer an invoice, they can click the button to pay online, and it takes them to the Stripe payment page.
If they print the invoice however, the button is obviously no longer there. The only way they can now make a card payment is to phone us.
It would be useful to include a shortened version of the payment button URL printed on the invoice. Or alternatively the ability to give them a link to a payment page where they can enter their invoice number and make a payment that way.