You need to be a billing admin to be able to update credit card details. You can find the steps to update billing admin here.
1. Go to 'Settings' by clicking on the profile card on the bottom left and then click on 'Subscription'.
This will direct you to the payment app. You can also directly login to the payment app with the same login credentials that you use for Zegal app.
2. Click on 'Manage payment methods'.
There you will have the option to: add a card, remove a card and set a card as default payment.
How to add a card
Click on 'Add a credit card' and fill in the information.
How to edit, remove and set a card as the default payment method