To decide the value of the currency, these are the different parameters that are considered by the international market:

Demand for the currency in the global market
Supply and demand chain with total expectation for the future
Stability of political environment, natural resources, phase of technology growth, human capital,
Demand for treasury- It goes parallel with the value of the currency.

Different countries have their respective currencies. The U.S. dollar of the United States is also known as the almighty currency for global trading.