"An Executive Order is a signed, written, and published directive from the President of the United States that manages operations of the federal government" (American Bar Association).
EOs require the government "to take specific actions to ensure "the laws be faithfully executed."" (ACLU). However, EOs cannot override federal laws and statutes. Statutes must be passed by Congress and signed by the president, and EOs cannot preempt this process. Additionally, control over taxation, spending, and certain war powers comes from Congress as written in the Constitution. An executive order cannot be a new statute, but it can tell federal agencies how to implement a statute. For more information, visit the American Civil Liberties Union page.
The US Chief Information Officers Council (CIO.gov) states: "An EO is a declaration by the president which has the force of law, usually based on existing statutory powers, and requiring no action by the Congress."