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 into the Administration Panel of your Joomla! website
Open a browser window and enter the address (URL) for the Administrator of your website. This would be something like https://www.your_site_name_here.com/administrator/. Once the page is loaded, log in as a 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 Users: New Page
Navigate to the Users → Manage → Add New User → Account Details tab page from top menu.
Now, let's fill in the user Account Details.
Name - this field will contain the user's real name, like John Smith.
Login Name - the name to be used to log into the site, like jsmith or yellowbird67.
Password - here you can enter a temporary password that you will send to the user so it can login for the first time. The user will be able to change this to something that is easy to remember or more secure. A good rule of thumb for choosing a safe password is to use lower case letters together with upper case letters and numerals while having a minimal length of six characters.
Confirm Password - here you have to reenter the previously-chosen password just to make sure there was no typographical error in the first one.
Email - here you enter an email address for the user.
Receive System Emails - Set if the user should receive system-relevant e-mails. Unless the user is an Administrator or Super User you probably want to set this option to No.
User Status - 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 Blocked to disable the account.
Require Password Reset - Setting this option to Yes requires the user to reset their password the next time they log into the site.
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 possible". Normally, you wouldn't want to assign the Super User 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.
Backend Template Style - Select the template style for the Administrator Backend interface. This will only affect this User.
Backend Language - this parameter sets the administration panel's language.
Frontend Language - this parameter sets the website's frontend 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.
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.
Once you are done entering all the information above, click the Save & Close button.
If you have enabled the user by setting the User Status field to Enabled, the user is now able to login using the username and password you have set.
Disabling/Banning a User
In order to disable or ban an existing user - not allowing them to log into the site - you will have to log into the Administrator 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 User Status option to Blocked and press the Save & Close button.
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 User Status option to Enabled.
Deleting a User
In order to delete a user from your database, log into the Administrator as described above and choose Site menu → User Manager from the top menu. On the opening page, select the checkbox to the left of the name you would like to remove and press the Delete button above.