As an owner of an Invitation-Only community, you can send invite notifications to each user you wish to become a member. These notifications automatically show in the user’s Inbox.
To invite user to join your community:
From the Communities page, click Manage Communities.
A list of all communities displays.
Click Invite next to your community.
The Invite link, if available, displays in the Membership column for each community to open an invitation dialog box:
Select one or more users.
Use Ctrl+click to select more than one noncontiguous user names.
Use Shift+click to select more than one contiguous user names.
Click Invite as Producer or Invite as Consumer to send the invite.
The users are invited and see a notification in their Inbox on their next login: