Inviting people to your team is a part of Know Me Toolbox Plus. You can receive invitations without an active Know Me Toolbox Plus subscription, however.
From the Toolbox, tap Followers
To invite someone as a Follower, tap "Who Follows Me." To invite someone as an Administrator, tap "My Administrators"
Tap the Invite arrow at the bottom right of the screen
Enter their email address and tap the green check mark