What's the role of the Secretaries ( e.g Secretary of State, of Defense, of Treasury, etc ...)?

Question

The exact role please !

Answer 1

The exact role is difficult because they manage very large departments with a lot of different sub units doing a lot of different things.  But in general, they implement public policy through the bureaucracy and try to implement the President's program.  They develop budgets and in coordination with the Office of Management and Budget, try to make the overall budget fit with the President's goals.