Go to Manage > Groups.
From the Options menu, choose Invite trainees.
Select the course from the dropdown menu (e.g. Forklift Operator (Unit Standard 10851)).
Enter the emails for the trainees you are inviting.
The group will already be preselected; add another group if you need to.
Click Send Invitations.
They will receive an email from you with a link to accept the course invitation.