You can easily manage your payment methods and add or edit credit cards from within your account.
How to add a credit card
Click Settings in the main navigation menu.
Under Marketplace, click Billing.
Click Add a credit or debit card.
Enter your credit card details.
Click Add card.
How to edit a credit card
Click Settings in the main navigation menu.
Under Marketplace, click Billing.
Click the ... action button next to the card you'd like to edit, then click Edit.
Edit the card details, then click Save.