How to set up user registration?

Dear Experts,
Currently, when users want to comment it says “You must be logged in to comment”

But this takes them to a page with the Log-In BUT with a
“User registration is currently not allowed”

I went to my dashboard and couldn’t find any option to set up a registration page. Nothing under Privacy and nothing under Discussion.

Where should I be looking? Or do I actually need to install a plug-in for this?

Thanks!
Renman