An online tutorial called FED 101 at the website of the Federal Reserve System of the United States includes a section called “How does the Fed create money?” The illustration here is from an animation of the some effects of interest rates. It links to a full page that explains and illustrates inflation. There are several other explanations of the fundamental elements of the workings of the Federal Reserve System in the FED 101 material.
There is a concise definition of the Federal Reserve System on the website of its bank in San Francisco. The theme of the definition: “The Nation’s Central Bank.” Topics include “Why We Need a Central Bank” and “The Fed is First and Foremost the Nation’s Money Manager.”
Both of these websites contain many informational sections and links out to other excellent open, public access sources on the Fed, an institution at the center of the United States economy and of enormous influence on money across the world.