The foreign exchange market works through financial institutions and operates on several levels. Behind the scenes, banks turn to a smaller number of financial firms known as "dealers", who are involved in large quantities of foreign exchange trading. Most foreign exchange dealers are banks, so this behind-the-scenes market is sometimes called the "interbank market" (although a few insurance companies and other kinds of financial firms are involved). Trades between foreign exchange dealers can be very large, involving hundreds of millions of dollars. Because of the sovereignty issue when involving two currencies, Forex has little (if any) supervisory entity regulating its actions.
The forex market uses symbols to designate specific currency pairs. The euro is symbolized by EUR, the U.S. dollar is USD, so the euro/U.S. dollar pair is shown as EUR/USD. Other commonly traded currency symbols include AUD (Australian dollar), GBP (British pound), CHF (Swiss franc), CAD (Canadian dollar), NZD (New Zealand dollar), and JPY (Japanese yen).
The main trading centers are London and New York City, though Tokyo, Hong Kong, and Singapore are all important centers as well. Banks throughout the world participate. Currency trading happens continuously throughout the day; as the Asian trading session ends, the European session begins, followed by the North American session and then back to the Asian session.
To find out how many euros it costs to buy one U.S. dollar, flip the pair to USD/EUR: divide 1 by 1.3635 (or whatever the current rate is). In this instance, the result is 0.7334. It costs 0.7334 euros to buy one USD based on the current market price. The price of the currency pair constantly fluctuates, as transactions occur around the globe, 24 hours a day during the week. 
Most brokers also provide leverage. Many brokers in the U.S. provide leverage up to 50:1. Let's assume our trader uses 10:1 leverage on this transaction. If using 10:1 leverage the trader is not required to have $5,000 in their account, even though they are trading $5,000 worth of currency. They only need $500. As long as they have $500 and 10:1 leverage they can trade $5,000 worth of currency. If they utilize 20:1 leverage, they only need $250 in their account (because $250 * 20 = $5,000).

During the 15th century, the Medici family were required to open banks at foreign locations in order to exchange currencies to act on behalf of textile merchants.[10][11] To facilitate trade, the bank created the nostro (from Italian, this translates to "ours") account book which contained two columned entries showing amounts of foreign and local currencies; information pertaining to the keeping of an account with a foreign bank.[12][13][14][15] During the 17th (or 18th) century, Amsterdam maintained an active Forex market.[16] In 1704, foreign exchange took place between agents acting in the interests of the Kingdom of England and the County of Holland.[17]
The MetaTrader 4 platform provides wide analytical opportunities. Each symbol can be displayed in 9 time-frames, allowing traders to see the price dynamics in detail. 30 built-in technical indicators and 24 graphic objects are available for the most comprehensive analysis of price dynamics. Combine these tools, identify trends, determine entry and exit points and with wide analytical capabilities of MetaTrader 4 you can thoroughly analyze market movements to catch the best time to trade.

Big news comes in and then the market starts to spike or plummets rapidly. At this point it may be tempting to jump on the easy-money train, however, doing so without a disciplined trading plan behind you can be just as damaging as gambling before the news comes out. This is because illiquidity and sharp price movements mean a trade can quickly translate into significant losses as large swings take place or ‘whipsaw’.

There are two main types of retail FX brokers offering the opportunity for speculative currency trading: brokers and dealers or market makers. Brokers serve as an agent of the customer in the broader FX market, by seeking the best price in the market for a retail order and dealing on behalf of the retail customer. They charge a commission or "mark-up" in addition to the price obtained in the market. Dealers or market makers, by contrast, typically act as principals in the transaction versus the retail customer, and quote a price they are willing to deal at.

The foreign exchange market assists international trade and investments by enabling currency conversion. For example, it permits a business in the United States to import goods from European Union member states, especially Eurozone members, and pay Euros, even though its income is in United States dollars. It also supports direct speculation and evaluation relative to the value of currencies and the carry trade speculation, based on the differential interest rate between two currencies.[2]
A forex or currency futures contract is an agreement between two parties to deliver a set amount of currency at a set date, called the expiry, in the future. Futures contracts are traded on an exchange for set values of currency and with set expiry dates. Unlike a forward, the terms of a futures contract are non-negotiable. A profit is made on the difference between the prices the contract was bought and sold at. Most speculators don't hold futures contracts until expiration, as that would require they deliver/settle the currency the contract represents. Instead, speculators buy and sell the contracts prior to expiration, realizing their profits or losses on their transactions.
Factors like interest rates, trade flows, tourism, economic strength, and geopolitical risk affect supply and demand for currencies, which creates daily volatility in the forex markets. An opportunity exists to profit from changes that may increase or reduce one currency's value compared to another. A forecast that one currency will weaken is essentially the same as assuming that the other currency in the pair will strengthen because currencies are traded as pairs.