"Money is an asset used as a medium of exchange that can be used to purchase goods or pay debts. Currency is liquid and universally accepted and is an integral part of the modern economic system.

Currency can be divided into two forms: physical currency and digital currency. Physical currency includes banknotes, coins, etc., while digital currency refers to virtual currencies based on the Internet and blockchain technology, such as Bitcoin and Ethereum.

The functions of money mainly include the measure of value, means of storage, medium of exchange and means of payment. Currency provides infrastructure and basic guarantees for people's economic activities through its different functions.

The right to issue currency is usually held by the government or the central bank, who are responsible for formulating monetary policy, regulating the supply of money and interest rates, and maintaining the stability and value of currency.

The circulation and transactions of currencies are affected by various factors, such as government policies, international trade, economic growth and inflation, etc. The adjustment and management of monetary policy is also one of the key factors to maintain economic stability.

In conclusion, currency is an indispensable part of modern economy and it plays an important role in economic activities. The issuance and management of currency needs to be highly valued and managed by the government and the central bank to ensure the stability and value of the currency. "