If the site contains a custom field, the fields that are applied to each subscriber can be viewed in this tab. Enable the subscribers to enter custom field information via Public Pages.
These can be manually entered or changed to custom fields per subscription here. Edit or delete custom fields associated with a subscription here.
Please be aware that this article is related to Advanced Billing's Subscription Summary function. The subscription summary is the place to perform all tasks necessary to manage customers’ purchases through Advanced Billing. You can learn more about the Subscription Summary by checking out this help article: Subscription Summary Overview.