Written record of presidential actions takes various forms, including executive orders, proclamations, press conferences and speeches, and bill signings. Whitehouse.gov is the official website of the White House, but only covers the administration currently in office.
Executive orders have the force of law but do not have to be approved by Congress, so they sometimes provoke controversy. Over 13,000 executive orders have been issued since 1789. A type of executive order which directs national security matters is called a Presidential Decision Directive.
Proclamations are also issued by the president, but have no force of law, and are generally statements on public policy. The most well-known presidential proclamation is the Thanksgiving Day proclamation, which was first issued by George Washington in 1789, and then every year since 1863. In a few cases, proclamations have been used to pardon individuals (most notably, President Ford's pardon of former president Nixon in 1974).
Transcripts of speeches, press conferences, and other presidential statements appear in the Compilation of Presidential Documents and are then compiled into the annual Public Papers of the Presidents. Public papers of all the presidents can be searched and downloaded at The American Presidency Project. Papers are also available starting from 1991 to the present (starting with the George H.W. Bush administration) at Govinfo.gov. BPL owns print copies of the official papers of all U.S. presidents (until 1957, many were published privately).
Other important published materials of the executive branch include Foreign Relations of the US (FRUS), published continuously since 1861. It contains official materials documenting American foreign policy. Now incorporating nearly four hundred volumes, it include materials declassified by the US Department of State. All volumes can be browsed and searched via the University of Wisconsin's FRUS portal.
Treaties in Force is published annually by the Department of State to provide information on treaties and other international agreements to which the United States has become a party. Texts of agreements to which the US is a party is available via the Treaties and International Agreement Series. You can also search pending and ratified treaty documents back to 1949 at Congress.gov.
The National Security Archive has been described by The Los Angeles Times as "the world's largest nongovernmental collection" of declassified documents. Many documents were obtained via the federal Freedom of Information Act. Included are declassified documents and other materials from the president and other branches of government. The site includes a section of "Electronic Briefing Books" on national security, foreign affairs, government secrecy, and other topics.
US Executive Branch Documents, 1789-1932 is a microfilmed collection of nearly all executive branch publications. Microfilmed titles in this set are listed in the BPL catalog (sample record here). Please consult reference staff for further assistance.
Many eighteenth and nineteenth century executive branch publications were actually published by Congress and may be available in other major microform sets and in the American State Papers and the US Congressional Serial Set. Both the ASP and the Serial Set have been digitized by the Library of Congress as part of its American Memory Project. Many volumes have also been digitized and are fully viewable and searchable at the HathiTrust Digital Library.