If you want to quickly create a new user account in your Unix OS, it ca be done with just one line
Adding new user accounts in Unix
To create a basic Unix user account with default settings, you need to know only one thing: the username.
The reason I say it as one word is because username (quite often referred to as "login") is not the actual name of the new person gaining access to your Unix system, but rather a single keyword uniquely identifying this user in your system. Most often, usernames are derived from real names of users – jsmith, johns or smithj for John Smith, just to give you a few examples.
The simplest way to add a new user to your system is to do run a command like this:
ubuntu# useradd jsmith