Unable to sign in MacBook Air

When I normally open my MacBook Air the only thing that would appear on the screen was enter your password. I would then all ready to go.

Tonight I done the same thing only thing is now it is asking for “Name” and below “Password”. I don’t know

what to put down for the “Name”

The upper right hand corner of the screen there’s a power symbol. I click on it and the only options are: Shut down, Restart or Sleep mode.

I have tried restart and **** down. The same thing appears on the Home Screen . I cannot get pass the Home Screen. I moved the curser to the top of the screen and the drop down will not appear. What do I do?