You have to be an Account Owner to be able to change your payment details.
To change your payment details -> please, access your account and click on your avatar at the top right side of your board interface -> select Payment Plan from the menu.
To proceed further, click on the Payment Details button in the Current Subscription Details panel (img.1).
Please, edit the payment details in the Subscription Plan panel and click on Update Details (img.2).
* Payment notification email: once you submit a payment, you will automatically receive an Invoice over the provided email. You can also download it from the Last Invoices|All tab.
You will get a system confirmation message notifying you that your payment details have been updated successfully.