Required documents only apply to jobs. To make sure that all required documents are present, in the job file click on the Docs tab at the top of the Job screen and select to view Required Documents. If none are in the list then they are either all there or none are required. You can also set this tab to view a list of required documents on this screen. These setting are found on the Tools button under Customize Display.
If you didn't choose a required document set when you added the job, you can choose one here by clicking Require Additional Documents.
To indicate that a document on the Required Documents list is not required, click the document and then click Remove Requirement.