The owner of a group can appoint any member present on the site, subscriber or not, as administrator or moderator for his group.

An administrator is in charge of managing members while moderators are in charge of moderating content. 

A member can be appointed both administrator and moderator. In this case, the wider rights prevail, i.e. administrator.

To appoint a moderator or administrator, go to the "Members" tab of your group and click on the three small dots next to the member's name. You can then click on "set as administrator" or "set as moderator".

If you want to revoke the rights of a member, click on "set as member". 

Web version : 

Mobile version :