When adding a new, or editing an existing inspection type, you can dictate whether a file upload against that type should be mandatory (cannot log an inspection of that type without a file/document attached) or expected (can log an inspection of that type without a file/document attached, but will warn you that it should contain one).
To do this, you need to access the Event/Inspection Types settings area.
Click on the Add Event / Inspection Category button
Choose whether the inspection type must have a document attached when logged (Mandatory Document Upload) or is expected to have a document uploaded (Expected Document Upload).
You can only choose one of the options.