Money means the currency and other liquid instruments of a particular country; it can also include demand deposits. Though every country’s central bank defines what does money means in that particular country. 

The supply of money means the entire stock of money circulating in a country’s economy (flow of money). Money supply can include cash, coins, savings account balance, and any other near money substitute.
Money supply in any economy can be measured in many ways using narrower or broader definitions of which classes of financial assets are considered to be money.

Effect of money supply in the economy:
Any increase in supply of money typically lowers interest rates, which in turn puts more money in the hands of consumers, thereby generating more investment opportunities, thereby stimulating spending. Increased money supply in the economy helps businesses to grow as there is an increase in purchasing power of consumer therefore, increased demand and when the demand increases, companies produce more and hence grow better. And vice-versa happens when the supply of money is restricted in the economy or reduced for a period of time. When supply of money lowered more than required, it can be one of the reasons for an economic recession.