How to enable access to new registered users on a private site

I cannot figure out how to enable new registered users on a private site using he admin panel. By default, access to the site is disabled until enabled. Since my site is hosted by IONOS, I know I can upload an updated yaml file for a new registered user and enable access, but I was told there was a way to enable access for a new registered user by using the admin plugin, but, when I use the admin plugin, it says the new registered user already has access permission enabled which is not correct. Is there a way to change the remote yaml file access state for a new registered user by using the admin panel? I don’t see any way.

If someone here told you this, could you please link to the post?

It wasn’t anyone on this forum.