Tech File is easier, but DHF more useful. DHF : A compilation of records that contain the history of the design, such as validations, verification, qualifications, environmental testing, project plans, risk management activities, meeting minutes,design reviews etc. Often this will include all revisions of a procedure, drawings, etc. also Clinical Trails is very important.
FDA ensure safety and efficacy.
But Tech file Shows snap shot of design. Design Dossier equivalent to FDA’s requirements for DMR+DHF