You can update your credit card information by visiting the manage billing page.
You can access the billing page inside Filerev by clicking on your user avatar menu and then selecting Manage Account.
Then click the Billing Portal button.
Next, you will see a page like the following and just need to click Add payment method.
Then type in your credit card details and make this card the default payment method by clicking the 3 dot button next to the newly added credit card number.