If you share a computer, you might not want everyone who uses your computer to see your username in the login window or fast user switch menu. To hide your name, MacIssues points out you’ll just need a little bit of Terminal skills.
The idea here is to hide you administrative user account so nobody even knows it’s there to be messed with. Provided you’re on OS X Yosemite or higher, you can hide your username pretty easily. Just run this command, substituting your username in for USERNAME:
sudo dscl . create /Users/USERNAME IsHidden 1
This will hide the administrative account from the login window, Users & Groups preferences, and the user switching menu, though you’ll still be able to manually login. It’s not super necessary for most of us, but if you have a lot of different users on a shared computer, it’s a nice way to make it a little tougher for people to tinker with your settings.
How to create hidden administrative accounts in OS X | MacIssues
via Lifehacker
Create Hidden Administrative Accounts in OS X from the Terminal