There are three types of privacy for groups: Open, Secret and Closed. In the description below you can find out the details about who can join these groups and what information they can see.

OPEN

Who can see the group? Any member of your community
Who can join? Any member of your community
Who can see what members post in the group? Any member of your community
Who can post within the group? Only members of the group
Who can send notifications? Only group administrators

SECRET

Who can see the group? Only group members
Who can join? Only contributors who have been assigned from Humand Admin.
Who can see what members post in the group? Only members of the group
Who can post within the group? Only members of the group
Who can send notifications? Only group administrators

CLOSED

Who can see the group? Any member of your community
Who can join? Any member of your community can request to join but a group admin must approve their request.
Who can see what members post in the group? Only members of the group
Who can post within the group? Only group members
Who can send notifications? Only group administrators

Users who have Backoffice permission to Manage groups will have access to the list of all groups, including secret groups. Although they may not be part of them (so they would not be able to log in), from the Admin they can self-assign themselves and then access their content.