You can change the status of the Requisition from Approved to Fulfilled upon the completion of the recruitment process. If you have hired the requested Employees then you can fulfill the Requsition. You cannot modify the Requisition if the status is 'Fulfilled'.
You have an option to setup an email event for this functionality. By using the Event ID: REJECT_APPLICANT, you can notify the applicants on the Rejection of the Application. Email notifications will be sent to the Applicants who are not offered/hired through the Requisition.
In order to perform this activity an Approved requisition should be available in IFS Cloud.
As a result of this activity the status of the Requisition changes to 'Fulfilled'