1) Mass Mail
This will allow you to mass mail all of your users in the system. This is great for alerting users to issues on the website or remind users to change and update their passwords on the system.
The permissions tab sets out what user group has access to the User Manager area of the website.
3) Allow User Registration
This option will either enable or disable the user registration on the website. By default this is set to YES.
4) New User Registration Group
Here you can set which group you would like users to be assigned to when they register to the website. By default they are assigned the the Registered user group.
5) New User Account Activation
This will define how accounts are activated on the website. You can choose from no activation, user activation or administrator activation. Choose either No activation or user activation for a more automated registration process. If you wish to have more control over who or what registers on your website then choose Admin.
Read more about user account activation
6) Frontend User Parameters
This will either show or hide the user parameters when they are logged in on the front end of the website. This should usually be left on SHOW.