Created in 1939 by President Franklin D. Roosevelt, the Executive Office of the President provides the President with help and support as he governs. Communicating the President's message and promoting the United States' trade interests abroad are among the tasks undertaken by this office. The Executive Office of the President is overseen by the White House Chief of Staff.
The role of the Office of Management and Budget (OMB) is to assist the President as he or she prepares the Federal budget, which includes evaluating the effectiveness of the programs, policies and procedures of Federal agencies.
The Vice President is the person, designated by the Consitution, to succeed to the Presidency in the event of a vacancy caused by the President's death, disability, resignation, or impeachment.
In addition to the Office of Management and Budget and the Office of the Vice President, the following are some of the other entities that exist within the Executive Office of the President. A complete list of offices and agencies in the Executive Office of the President is provided by USA.gov.