Log in to the eBay website and click My eBay in the top-right corner.
Go to Account settings.
Navigate to Payment Methods and select Add payment method.
Enter your credit card details and billing information.
Click Save to complete the setup.
(eBay may perform a small pre-authorization charge to verify the validity of the card. Once verified, the card will be successfully added.)
Notes
Ensure you are operating on a secure network when adding your payment method.
It is recommended to enable two-factor authentication (2FA) to enhance account security.