The billing portal is set up per realm. If you are the admin for multiple realms, you will need to access different instance of the billing portal for each realm.
Log into the first Quickbase realm for which you want to review payment information.
Go to the Admin Console. This can be done from the My Apps page by selecting Manage my account.

Select the Manage Billing button.

You will be redirected to the billing portal. From here, you can view information about your account or manage your payment method.After you have finished reviewing the information for this realm, log out of the billing portal.
Select your name.

Select Log Out.

You will be redirected to the billing portal login page. Close out of this page.

Return to Quickbase and log into the next Quickbase realm for which you would like to review billing information.
Repeat the steps above to access the billing portal for that account.
Note: Log out of the billing portal before signing in to a different Quickbase realm. If you don't, you'll see information for the previous realm.