Linux is a multi-user environment, which means more than one user can use the system at one time. Granted, that mostly takes the form of console access (via SSH), because you can't easily have two ...
When I need to work with Linux user accounts, I tend to default to the command line. Sure, there are GUIs for this purpose, but I find the command line to be more efficient and effective at this task.
The new Add User window in Ubuntu 17.10. 2 ways to better secure your Linux home directory Your email has been sent If you want to further secure your Linux machines, there's no place like home.