What are 2-3 types of money that serves primarily as a medium of exchange?

Two types of money that primarily serve as a medium of exchange are Fiat money and digital currency. Fiat money, such as the U.S. dollar or euro, is government-issued currency that has value because the government maintains it and people have faith in its worth. Digital currency, like cryptocurrencies (e.g., Bitcoin), facilitates transactions online, allowing for peer-to-peer exchanges without the need for traditional banking systems. Both types enable the buying and selling of goods and services in an economy.