Fiscal policy is the national government’s tax and spending choices. In the United States, Congress and the Administration set those decisions; the Federal Reserve does not.
Monetary policy is what a central bank—such as the Federal Reserve—does to pursue goals like price stability, maximum employment, and stable growth. The Fed mainly influences short-term interest rates and broader financial conditions through tools such as its federal funds rate target.
The two interact indirectly: when the Fed’s policy committee reviews the outlook, it weighs how current and expected fiscal policy may affect growth, jobs, and inflation, then sets monetary policy accordingly. Source: Federal Reserve — Monetary vs. fiscal policy FAQ.