If you want to change the credit card you use for paying subscription, you can do so in "Subscription management." To do so, click on your name in the main menu header and click on "Manage subscription."

This will take you to your account settings; each of your projects have separate billing - select the one for which you'd like to edit your credit card and click "Manage subscription."

You will be redirected to billing management in Stripe, where you can add a new credit card. Click on the three dots to make it the default card used for billing.