'Create Apple Account' option is grayed out on my MacBook Pro

I have a macbook pro and i cant add my apple account. the button called 'create apple account' is gray and i cant press on it. I dont know how to fix it.

As well as that, when i go to 'general' then to 'about' i change the name of the computer however when i go to my devices the name has not changed.

[Re-Titled by Moderator]