You can update your payment information at any time by going to Settings > Billing Information.
Your Default Payment Method will be the payment method used to pay your invoices.
Change Your Payment Method
To change your payment method:
Go to Settings in the left navigation menu.
Click Payment Methods under Billing.
Enter your Billing Information.
Add a new Credit Card or PayPal Account.
Remove Payment Methods
We need to have at least one payment method on file if you've launched a campaign. To remove extra payment methods, click X. If the X option is not shown, it means that there is only one payment method in the billing account. The payment method must be replaced in order for Remove to be available.
Removing a payment means that the payment method can't be used as backup anymore. We recommend uploading at least one other payment method as backup to avoid any interruption in campaign activity.
Learn more about understanding your Billing History.