For anyone interested in the actual answer, the Federal Reserve "prints" money (aka, expands the money supply) in three ways:

It can ease its reserve requirements for banks, which makes more money available for banks to lend (It's been 0% since 2020, which means banks can lend out 100% of your deposit and keep 0% on hand)

It can lower the discount rate at which it lends money to other banks, which makes it more attractive for them to borrow

It can conduct "routine open market operations" whereby it purchases Treasury securities from financial institutions.

This last one is what most people think of when they say the government prints money. The Federal Reserve buys those Treasury bonds from the U.S. government with "newly created electronic funds and the bank adds those funds to the seller's account."

The Fed literally creates new money, digitally, with a few keystrokes, and uses it to buy bonds from the government.