Facebook offers many payment methods. You can use your credit card, PayPal, or even a Facebook gift card. If you use PayPal to pay for Facebook ads, your PayPal information is saved, and you can edit it in the Payment Methods row. To add a credit card to your payment methods, follow these steps: In the Payment Methods row, click the Manage link.
https://www.dummies.com/social-media/facebook/how-to-manage-your-facebook-payments-settings/

