"User zone" on my WordPress

Hello, i have a basic WordPress webesite (I’m not using any template).
I want to know if it is possible to have an “User zone” on my Website.
For exemple, when someone post a comment, he can’t be a member, he just post as a “temporary member”.
I just want to have real members on my wordpress 🙂
How it’s possible ?
Thanks, and sorry for english…