When you enable the Invite-Only option, registration to your community becomes restricted. Only users who receive an invitation email or a share invitation link can join your community.
When Invite-Only is enabled, the Join button is removed from the registration page. Existing members can still log in with their credentials.
Who can send invitations
The following roles can invite users to your community:
Admins
Moderators
Members (when enabled)
For details on how members use the invitation feature, see How to invite new members.
How to enable Invite-Only mode
Log in with your admin account.
Click your profile picture in the top-right corner.
Select Administration.
Click Settings.
Go to Site Settings.
Toggle Invite-only on.
Click Update.