To understand how forex markets work, one has to understand what exactly constitutes the forex market, the institutional framework that drives this market, and importantly the process of currency price determination.
Foreign exchange market is no different from any other market where buyers and sellers meet to buy or sell a commodity for a specific price. The only difference in forex markets being, it is the “currency” that constitutes the commodity, and the price at which it is exchanged conforms to the foreign exchange rate for that currency at that point in time.
Export earnings of corporations, overseas remittances, and investment flows (direct or borrowed capital) constitute the main sources of foreign exchange. Individuals and entities who receive foreign currency are the primary market suppliers and they may sell foreign currency to licensed exchange dealers who in turn may pass it to other dealers in need of foreign exchange. The Central banks may sell foreign reserves to make market adjustments, and on the other side companies would need to buy this foreign exchange to make overseas payments. This creates a market for foreign exchange wherein a person may sell a currency today and probably emerge as a buyer the very next day.