When login/sign-up are walls and when they not?

1. What are login walls?
2. Is there a single word for login register?
3. What is mobile login?

What are login walls?

login wall (plural login walls) (informal, Internet) A website notification that prevents an unregistered visitor from viewing any content until signing up or opening an account.

Is there a single word for login register?

The name makes it clear it's the entry point. The only other name that springs to mind is account, but I think that would be better kept for something that allows you to change your email, password, settings etc.

What is mobile login?

It is the process of registering or accessing a user's account by using a phone number. The user enters their phone number as username and receives a one-time password (OTP) on their mobile phone, entering which they can log in.