Most countries have their own national currency such as the US dollar, the UK pound, the Japanese yen and the Thailand baht and these are of course necessary for making payments for goods and services within each country’s borders. However, in a world where we are traveling more and more and where countries are increasingly trading with one another, foreign currency is required to pay for cross-border sales of goods and services. This means that there must be some mechanism in place to provide access to foreign currencies, so that payments can be made in a form that is acceptable to the seller, and thus the need for a foreign exchange market (or forex market which is simply short for FOReign EXchange).
In its simplest form foreign exchange refers to money which is denominated in a currency other than your own. For example, if an individual exchanges his own currency for the currency of another nation then he acquires foreign exchange. Of course we often think of foreign exchange in terms of tourism and most of us will have traveled abroad either on holiday or for business and exchanged currency on arrival at our destination to pay hotel and restaurant bills and for taxis, sightseeing and shopping. However, foreign exchange is not simply limited to the relatively small sums of money handled by tourists, but applies equally to larger transactions such as the exchange of hundreds of millions of US dollars when a US company buys another company which is based overseas. Money Transfer
Broadly speaking, in the US any money which is denominated in the currency of another nation would be termed as foreign exchange and it is important to remember that we are not necessarily talking here about cash. Foreign exchange can also consist of money which is available through a line of credit (such as a credit card) or that is held in the form of traveler’s checks. In other words, we still talk about foreign exchange for any negotiable instrument which is denominated in a currency other than the US dollar.
When we talk however about the foreign exchange market we are not really concerned with the exchange of small sums of currency by tourists, but are looking at foreign currency which is exchanged between an international network of foreign exchange dealers and is normally exchanged in what most of us would see as being very large sums of money. For example, one of main players in foreign currency trading is the major banks and here a US bank might need Japanese yen and thus deposit several million US dollars with a Japanese bank in exchange for Japanese yen.