In the notifications tab of a vacancy you can set notifications for:
New Applicants: Specify who receives a single notification via email every when a new applicant applies.
New Scorecards: Specify who receives a single notification via email when creating a new scorecard. You can only select hiring leads for that vacancy.
Pipeline Stages: Select who receives a notification when moving an applicant to the next stage.
You can only select someone who is a hiring lead for that vacancy or an admin.