The Joomla User menu is where you can add/edit user settings, add users to groups to determine what items they are allowed to edit, set up the user access levels to control which users can see which pages within your site, and some documentation capabilities with the use of notes. 
Photo of user options

User manager: 
The User Manager area is where individual user accounts are managed.  This is where you add new users and define which website areas the user is allowed to access or edit.

usermanager
How do I add a user? 
You can manually add users by clicking on the "New" icon.
Photo of add new user icon 

On the Account Details tab, you must fill in the user name, login name, and email address. The Login Name must equal the person's BlazerId.  Do NOT enter a password. Required fields are highlighted in red.
New user account detail requirements 
Next, click to the Assigned User Groups tab. Place a check mark by the user group the user should be assigned to. In this example, the user is assigned as an administrator.
Assign the new user to a group
Click the Save & Close icon to save the new user account.
Save the user icon