You need to have administrator privileges to be able to change your payment details.
To change your payment details -> click on your username at the top right corner of your screen to open the Account Menu -> select Payment Plan.
Click on the Payment Details button in the Payment Panel.
Change the details you wish, e.g. Payment Notifications Email, credit card details etc. -> click on Update Details.
Note: Once you submit a payment, you will automatically receive an Invoice over the provided email in the Payment Notifications email field. You can also download it from the Payment panel ->Payment Details->Last Invoices/All.
Your payment details will be updated and a confirmation message will be displayed on your screen.