If you are asking about the line of Presidential succession if the President dies in office or resigns, it is the President, VP, Speaker of the House, President Pro-Tempore of the Senate and then the Secretary of the Cabinets, in the order of their creation, with Sec. of State first. Since the ratification of the 25th Amendment, if there is a vacancy in the office of VP, the President nominates a VP who then takes office upon confirmation by a majority vote of both Houses of Congress.