Please note: most (±95%) of the U.S. money supply is not created by the Federal Reserve, but by the U.S. commercial banks as deposits when they make loans. [1] Alternatively you can read the Bank of England report on Money creation. [2] It's about the British economy but goes into further detail and the monetary principles are the same in every modern country.
[1] https://sec.report/Document/0001582202-21-000003/?__cf_chl_j...