Some communities allow you to invite other people to join.
If enabled for your community, you can invite people from outside the community to
join. When you send an invitation, they receive an email with instructions on how
they can set up their account in the community.
To invite people to join the community:
In the main navigation menu, click People.
This may be located under the Browse menu.
In the left pane, click Send Invites.
You won't see this option if your administrator has disabled the ability to
invite people from outside to join your community.
Enter a complete email address of the invitee.
You can send invitations to more than one person by adding their email
addresses in the box and separating them by commas (",").
Edit the note if you want to tailor it for your invitees.