An executive order is an action which does not require the approval of the Congress, by the President. It cannot contradict or override any law, but can direct agencies in the executive branch in accordance with law. For example, only the President can issue an Executive Order for a budget sequester, by law. Conservatives are often critical of executive orders for how they bypass the United States Constitutional process for enacting new laws.
Barack Obama issued 276 executive orders in total. During his two term Presidency, Ronald Reagan issued 381 executive orders. One must look at the content of executive orders rather than the number issued to determine whether overreach had been committed by a president.
An advisor to President Bill Clinton, Paul Begala, once joked: "Stroke of the pen. Law of the Land. Kinda cool."
Presidents and Executive Orders