Final answer:
Banks create money through the fractional reserve banking system by lending out a fraction of the deposits they receive, which increases the money supply.
Step-by-step explanation:
Banks create money through the fractional reserve banking system. This system allows banks to hold only a fraction of the deposits they receive, while the rest can be lent out to borrowers. When a bank makes a loan, the money is deposited into the borrower's account, increasing the overall deposits in the banking system and effectively increasing the money supply.