You can enable user registration within the support portal. To enable this, please go to Support → Settings → General Settings → Page settings.
There are three options:
SuportCandy has default registration with minimum required fields which will load on the same page when visitors click on Register now link.
This will redirect visitors to the default WordPress registration page.
If you have a custom user registration page set, you can enter its URL so that visitors will be redirected to it when they click on Register now link.