billwerk automatically provides you with a hosted customer self-service portal and hosted self-service checkout pages for all plan variants.
In "Settings > Integration > Self-Service" you can set which customer data is required, optional or hidden. Required fields must be filled during registration, optional fields can be filled and hidden fields are not visible during registration and in the customer portal.
Hint: Custom fields cannot be displayed or filled via the hosted signup and portal. To do so, you need to customize your website using SubscriptionJS.