Log in to an administrator account.
Click the battery icon in the upper right corner.

A menu will appear, click the gear icon.

Note: You can also access Settings by using the desktop search bar.
From the Settings menu that appears on the left, select the Users option.

Click Unlock in order for the system to allow you to make changes. You may now be asked for your password.

Click Add User at the bottom of the users list, and you will be able to add a new user account

The Add User dialog will appear, please fill in the information required to create the new user: select the account type, enter the name of the user account and edit the password settings.

Click the Add button at the top right of the dialog, and the new user will be created.