Money takes various forms including coins, banknotes, and records of debt. It functions as a medium of exchange, unit of account, and store of value. Historically, money transitioned from livestock and commodities to precious metals and eventually fiat currency issued by governments. In India, the rupee is the currency, printed by the RBI and minted by the IGM. Money supply refers to the total amount of money available in an economy and is defined and measured differently by central banks using metrics like M0, M1, M2, M3, and M4. The RBI uses tools like reserve ratios, interest rates, monetary policy, and open market operations to control money supply and stabilize prices.