The Federal Register includes federal agency regulations, proposed rules, public notices, and presidential documents. After regulations are adopted they are arranged by subject and published in the Code of Federal Regulations.
You can access the Federal Register and the CFR through GovInfo.gov
To comment on proposed regulations go to regulations.gov
Presidential communications consist of executive orders, proclamations, directives, and administrative orders. You can find recent presidential communications in the following resources:
Compilation of Presidential Documents - published every Monday and is the official publication of presidential statements, messages, remarks, and other materials released by the White House Press Secretary.
Whitehouse.gov - provides access to presidential actions, press briefings, speeches and remarks, and nominations and appointments.
Communication from previous presidents is compiled by the National Archives and Records Administration and published in the Public Papers of the Presidents series
Another source for presidential documents is a presidential library. Presidential Libraries are repositories for the papers, records and historical materials of the presidents.