If there is more than one applicant which is required to be communicated with separately, they can be added here.
To add an additional applicant click on the button. This will open the client screen where you can choose an existing client as the additional applicant or add a new one. See the Client's Screen for more information.
See How do I use the navigation buttons? for further help on the navigation bar.
Information on the other tabs on the applicants screen is available here: