What is the difference between a contact and an applicant?
A contact is always associated with an organisation and you can generally access contacts through any of the people searching screens (Search People or any application with the Contacts tab).
An applicant is always associated with an Applicant Folder and you can only access applicants through the Applicant Tracking system if you have access to the folder where the applicant is stored.
This approach is designed to ensure applicant confidentiality.
You can, however, designate an applicant as a contact or a contact as an applicant. This approach is useful in some environments, such as placement agencies where contacts become applicants and applicants become contacts.