If you're a system admin, user admin, or group admin, you can use the Admin Console to add, remove, and edit accounts for users and groups.
Note that this guide does not describe how to set permissions for users and groups. You can set permissions if you're a system or space admin, but not a user or group admin. For more on setting permissions, see Managing Administrative Permissions.
User accounts represent people who have access to the application. User groups collect user accounts in order to make it easier to manage access to the application's features.
A user account represents a person using the application. Each user account has associated content, including the person's profile. For all users, you can use the console to change their user name and password, view and delete the content they've created, and view and edit their profile information. You can also disable a user, such as when they're no longer involved, but you want to hang on to their content.
For more, see Managing User Accounts.
A user group collects user accounts, typically in order to make it easier to grant all of the collected users certain permissions. For example, you might create a group of human resources workers so that you can give them (and only them) permission to view potentially sensitive information about employees in a "Benefits" space. A user group is made up of members, who typically aren't aware they're in the group, and admins, who have Admin Console access through which they can manage user group settings and membership.
For more, see Managing User Groups.
The work you do with user accounts and user groups will depend heavily on whether the application is connected to an external user identity management system. Generally speaking, when you add user accounts and user groups using the admin console, you're adding that data to the same database used to store content. This isn't typically the case if the application is connected to an external user identity system such as LDAP or Active Directory. In that case, much of the information about users will be coming from -- and managed within -- the external system.
By default, even if your community uses an LDAP or Active Directory database (or some custom solution), the users you add through the Admin Console will be added to the application's database and not the external system. It is also possible that user accounts will be managed by the external system, but the groups they're members of will be created and managed locally in the application database. How user group are managed is defined when the external system is connected to the application.
You can configure the application so that users can register on their own. When you enable user-created accounts, people can register by entering basic required registration information (such as a user name and password), along with user profile information. They can also invite other people to join the community.
For information on configuring registration, see the Configuring User Registration.