What Is Currency, and how it works???

Currency is a medium of exchange for goods and services. In short, it's money, in the form of paper and coins, usually issued by a government and generally accepted at its face value as a method of payment.

Currency is the primary medium of exchange in the modern world, having long ago replaced bartering as a means of trading goods and services.

In the 21st century, a new form of currency has entered the vocabulary and realm of exchange: the virtual currency, also known as cryptocurrency. Virtual currencies, such as Bitcoin and Ethereum, have no physical form or government backing in the United States. They are traded and stored electronically.
KEY TAKEAWAYS
Currency is a generally accepted form of payment usually issued by a government and circulated within its jurisdiction.
The value of any currency fluctuates constantly in relation to other currencies.
Currency is a tangible form of money, which is an intangible system of value.
Many countries accept the U.S. dollar for payment, while others peg their currency value directly to the U.S. dollar.
Cryptocurrency is a 21st century innovation and exists only electronically.