Adding a new user
From Joomla! Documentation
Adding a new user
A user is a person (or group of persons) who has authenticated itself by providing the registration data you requested. Normally, you create user accounts in order to grant access to exclusive parts of your site or allow your visitors to post their content.
In order to create a new user you will have to go through the following steps:
1. Log in to the administration panel of your Joomla! web site
Open a new browser window and enter the corresponding URL. This would be something like http://www.your_site_name_here.com/administrator. Once the page is loaded, log yourself in as the site administrator. Please note that other accounts might not have the rights to add new users, depending on the granted access level. More about the access levels later in this tutorial.
2. Open the User Manager
After logging in, go to the Site menu item, situated in the upper-left corner, right under the green bar separating the site header from the content area. In the opening menu select User Manager.
3. Add the new user
Name - this field will contain the user's real name, like John Smith.
Username - this would be the user or login name to be used to log in to the site, like jsmith or yellowbird67.
New password - here you can enter a temporary password that you will send to the user so it can log in for the first time. The user will be able to change this later to something that is easy to remember. A good rule of thumb for choosing a safe password is to use small letters together with capitals and numbers while having a minimal length of six characters. A good example would be p9HWc0Ak.
Verify password - here you have to reenter the previously choosen password just to make sure there was no typo in the first one.
Email - here you enter an email address for the user.
Receive System E-mails - Set if the user should receive system relevant e-mails. If the user is an Administrator or Super Administrator you probably want to set this option to "No".
Block user - here you have the possibility to disable a previously created user account without deleting it. This option might be useful for banning users until they (or you) take a certain action. Simply set this option to Yes to disable the account.
Assigned User Groups
Choosing the correct group to assign your user to may be crucial for your site's security so pay attention when setting this up! There is no golden-rule for choosing the user group except maybe for this one: "Keep the rights as low as posible". Normally, you wouldn't want to assign the Super Administrator or even Administrator role to just anyone. The Manager role is somewhat weaker but still strong enough to compromise your site's content. In 99% of the cases you will assign your users to the "Registered" group, thus only allowing them front-end access. In case you need more granularity of the access levels you might consider a third-party extension from the Extensions directory.
Back-end Language - this parameter sets the administration panel's language.
Front-end Language - this parameter sets the website's panel's language when the user is logged in.
User Editor - this parameter specifies which one of the built-in editors the user will be using while editing the information on the site.
Help Site - here you can specify the location of the help files. These can be read from the files installed on your server (Local) or from the the Joomla! site (help.joomla.org). I usually prefer setting this option to help.joomla.org as this information tends to be more up to date.
Time Zone - well, this speaks for itself. Here you can set the user's time zone. This information will be used wherever time and date is displayed to the logged in user.
The Contact Information field will show the user's contact data if there is a corresponding entry in the Contact Manager.
Once you are done entering all the information above, click the Save button (the floppy disk icon in the upper-right corner).
If you have enabled the user (by setting the Block User field to No), it is now able to log in using the usename and login you have set.
Disabling/Banning a user
In order to disable or ban an existing user - not allowing them to login to the site - you will have to log in to the administration panel and open the User Manager from the Site menu -> User Manager. In the user list select the corresponding user by clicking on its name. In the newly opened panel, set the Block User option to Yes and press the Save button (the floppy disk icon in the upper-right corner).
Please note that this method will not delete the user account but will only disable it. You can always re-enable it by setting the Block User option to No.
Deleting a user
In order to delete a user from your database, log in to he administration panel as described above and choose Site -> User Manager from the top menu. On the opening page, select the checkbox to the left of the user's name you would like to remove and press the Delete button in the upper-right corner.