Where is the users registration data and how can I managed it?
All custom-fields can be found on user profile page. Just make sure you've added the custom fields for Profile Tab too. Please read this addon documentation. For example, here you can see that fields on profile home page: https://wpforo.com/docs/root/addons/wpforo-user-custom-fields/user-profile-page/
To manage any of these fields you should go to that user profile > account page. However before that you should add all fields in account tab too: https://wpforo.com/docs/root/addons/wpforo-user-custom-fields/account-setting-form/