What is an additional credit cardholder?

This is a person who can use the card, but is not responsible for the debt. Both cardholders have a card and share the credit limit. However, unlike with joint current accounts where both account holders are liable, the primary credit cardholder is solely responsible for the debt. So as the main cardholder, you will be responsible for any spending made by additional cardholders. You'll need the permission of the additional cardholder to complete this application.