Hi @RobertChura ,
Thanks for posting on the Instructure Community!
While the free-for teacher edition of Canvas has some limitations due to admin-level features not being available, there are still other features you can take advantage of to control registration and access to your course.
The first thing you can do is have your students enter a join code when they create their free for teacher student account. This join code can be enabled / disabled anytime in your course settings. It must be enabled for you to be able to see the join code as well as sending your students a join URL.
Another possible solution for this if you don't want to use a join code upon sign up would be to have your students just create their accounts, but then you add them manually as the teacher using the emails they signed up with. While this works, I usually tend to stick to the first option I provided you with, as I find things work much smoother that way.
I hope this helps a bit, please reach out with any additional questions or concerns that you may have!
All the best,
Noah