Admin Only - Invitations from the admin(s) are automatically approved. Members can invite other users, and any user can join the group via the ‘Join’ button or ‘Referral’ link but will need approval from the Admin(s).

Members and Admins -  Invitations from Admin and members are automatically approved. Any user can join the group via the ‘Join’ button or ‘Referral’ link but will need approval from Admin.

Open - Invitations from Admin and members are automatically approved. Any user can join the group via the ‘Join’ button or ‘Referral’ link without the need for approval from the Admin or members.