Candidates (or applicants) are individuals that have applied to your job postings or have been added manually to your ATS. Candidates for a job posting are individuals that have applied to the job posting or have been added from another job posting or your candidate pool. Candidates in your candidate pool are your overall candidates that have applied to all of your job postings.
For additional information about the candidate's page and related functions, you can refer to any of the resources below: