Go to My account and click "Manage your credit cards".
Add a credit card: Click the "Add a credit card" button.
Enter your credit card details and then click "Add".
If an error message appears when adding a new credit card, it may be a refusal from your credit card company. Simply contact your credit card company to authorize this new transaction.
Please note, you can also add a new credit card to your account during the payment process when upgrading or downgrading your plan.
Set a default credit card: Simply click on the cogwheel icon and select "Set as default" on the credit card of your choice.
Remove a credit card: Click on the cogwheel icon and select "Delete".
Please note: if you only have one credit card on your account, it cannot be deleted. You will need to add a new one before you can delete the old one.