First off, simply fire up a terminal, and then for root access, type:

sudo su

It’d prompt you for the password, type it in.

Once you gain root access, type:

adduser username

It’d ask you to _enter new UNIX password. _type one, and retype when it asks you to

That’s it. Now it would prompt you for a few more details regarding the new user, but they arent important, just press enter, and soon, it’d  prompt you to confirm if the information is correct. Type y and enter. That’s it. Your new user account is up and running. To delete it via terminal, type the following command when root:

deluser username