Application forms appear when a candidate applies for an open job position. It allows you to capture relevant information about a candidate.
Each open job position has its own Application Form that you can add/remove the question base on the type of information you meant to capture.
Go to your open job → Application Form tab → click the Edit form button on the top left navigation.
You have the option to add custom questions and remove or re-organize existing questions. Remember that your custom questions are not carried over as you create new jobs, you will have to create new questions to fit the way you hire.
For example, if you are looking for a Personal Driver you might want to ask about his driving experience and a copy of his driving license.