Click on your name in the upper right-hand corner and select "Organizational Settings" from the drop-down menu.
Manage users will display all of the individuals with access to your account and their access level, listing them by name and email. You may delete any account access not your own.
Invite New Users will display previous invites, their status, and date sent on.
To add a new user, click on the green "Invite Users" button.
This opens a popup where you will enter the email addresses you wish to invite.
Select the box to the left of System Administrator if this is the access you'd like to grant. See System and Assessment Level User Access Overview for more information.
All invitations must be accepted within 30 days. If necessary, use the re-send invite button to send another invitation. You can also use the trash can icon to delete your invitation.
Once a new user has accepted the invitation you can change levels of access if necessary.