By default, once your program deadline has passed your applicants will no longer have access to their application. This means that your applicants can continue to access and update their applications up until the deadline, regardless of their application's status. Therefore, if you have evaluations that occur while the application is still open or you have an open or rolling deadline, you will want to lock the applications once they are submitted. This will ensure that any application that is under review is not going to be altered later on.
To lock applications once they are submitted, check the box next to "Lock Application on Submission" under Options and Customizations on the Program page.