Presidential issuances is a broad term used to cover executive orders, presidential proclamations, determinations, memoranda, administrative orders, and other issuances. The interesting thing about presidential issuances is that they tend to appear in multiple sources. This attests to their importance and the speed with which they public desires access.
The executive order is an extremely powerful tool in the hands of the chief executive. It has much the same power as an act of Congress, becoming part of the U.S. Code on occasion. Executive orders have been used to establish policy, reorganize government agencies, changes regulations, and affect how legislation is interpreted and implemented. National emergencies are typically declared via executive orders. It has been observed that presidents tend to go on and EO issuing spree at the beginning of the terms of service, and then again at the end. especially when party control of the White House will change to the other party.
From the time of President Washington until the end of 2018, there had been over 15,000 EOs issued.
EOs often (but not always) appear in the U.S. Code. Table IV in the back of the U.S. Code shows where EOs have been places in the Code.