If you're trying to update your payment information for the subscription, you can follow these steps:
Go to the Gear icon (⚙).
Select Account and Settings.
Click the Billing & Subscription tab.
Under Subscription status, click Subscribe Now on the right part.
Next, update the credit card information details.
Click Subscribe.
You can also scan through these links below which provide information about the different ways of updating your billing details in the system together with the accepted cards: