Forex, abbreviated as FX, is a term that refers to the simultaneous sale and purchase of currencies on an OTC (Over the Counter) market that works 24 hours a day, five days a week.
Forex markets are the world's largest financial markets, with a daily trading volume of around $3 trillion. Forex trading activities take occur in all of the world's main financial trading hubs; as a result, these trading operations tend to overlap across time zones.
The practice of exchanging one currency for another depending on the market's exchange rate, with these currencies being sold and bought in pairs, is known as forex, For example, in order to buy Japanese Yen, you must first sell US dollars, hence Forex currencies must be listed in pairs, such as GBP/USD, EUR/USD, or EUR/JPY.