Navigate to the “User Invitations” tab. Enter the email address for the user, and select the level of access they should have to this account and click on the “Invite” button. Checking the “Allow sign up through Google SSO” option will –
For new users: Allow the invited email to register through Google.
For existing users: Allow users who have signed up through Google to accept the invitation.
You should see the pending invitation listed in “Open Invitations”. Invitations expire after 3 days, and you may not have more than 10 pending invites at any one time.
Accept the invitation and link to the main account:
Your newly-invited user will receive an email like this:
Click on the “Accept this invitation” button.
New users: If Google sign up has been allowed on the invitation, you may sign up by clicking on the “Sign in With Google” button. In all cases you may also manually enter your registration details and click on the “Register” button. Existing users: Clicking on the link should immediately show you a success message stating that your e-mail address has been linked to the account.