If you have manager-level access, you can add users to your account and decide what level of access they have, what add-ons they have, and other various settings.
Here is how to add a user:
Click My Account in the lower left.
Click User Management.
You will now see a list of the users in your account:
Click Add Users.
Enter the email address. If you are adding multiple users, separate the emails with a comma. Press Enter, and then click Invite.
The new user will receive an email with a link to complete their user registration, and log in.
You will now see the new user(s) in the user list, and that they have been invited.
You can now select any of the users to edit their user settings.