The administrator of your account can add users to your company account. If you need to add new users to your account, go to the "User management" page and click on "Add a user".
This will open a window where you need to add the email-address of the new user and click "Invite".
The new user will receive an email with an registration link. When the user completes the registration, the user will appear in the list. You can revoke an invitation before the new user has completed the registration.
You can remove a user by clicking on the "Remove user" button right to the user name. If you remove a user, the user will not have access to your account with the next login.