From a historical standpoint, foreign exchange trading was largely limited to governments, large companies, and hedge funds. But in today's world, trading currencies is as easy as a click of a mouse. Accessibility is not an issue, which means anyone can do it. Many investment firms, banks, and retail forex brokers offer the chance for individuals to open accounts and to trade currencies. 

All forex trades involve two currencies because you're betting on the value of a currency against another. Think of EUR/USD, the most-traded currency pair in the world. EUR, the first currency in the pair, is the base, and USD, the second, is the counter. When you see a price quoted on your platform, that price is how much one euro is worth in US dollars. You always see two prices because one is the buy price and one is the sell. The difference between the two is the spread. When you click buy or sell, you are buying or selling the first currency in the pair.
It’s great having an effective once a day trading method and system. However, even a consistent strategy can go wrong when confronted with the unusual volume and volatility seen on specific days. For example, public holidays such as Christmas and New Year, or days with significant breaking news events, can open you up to unpredictable price fluctuations.
The blender company could have reduced this risk by shorting the euro and buying the USD when they were at parity. That way, if the dollar rose in value, the profits from the trade would offset the reduced profit from the sale of blenders. If the USD fell in value, the more favorable exchange rate will increase the profit from the sale of blenders, which offsets the losses in the trade.

International parity conditions: Relative purchasing power parity, interest rate parity, Domestic Fisher effect, International Fisher effect. To some extent the above theories provide logical explanation for the fluctuations in exchange rates, yet these theories falter as they are based on challengeable assumptions (e.g., free flow of goods, services, and capital) which seldom hold true in the real world.

Most developed countries permit the trading of derivative products (such as futures and options on futures) on their exchanges. All these developed countries already have fully convertible capital accounts. Some governments of emerging markets do not allow foreign exchange derivative products on their exchanges because they have capital controls. The use of derivatives is growing in many emerging economies.[58] Countries such as South Korea, South Africa, and India have established currency futures exchanges, despite having some capital controls.

Before the Internet revolution only large players such as international banks, hedge funds and extremely wealthy individuals could participate. Now retail traders can buy, sell and speculate on currencies from the comfort of their homes with a mouse click through online brokerage accounts. There are many tradable currency pairs and an average online broker has about 40. One of our most popular chats is the Forex chat where traders talk in real-time about where the market is going.

Despite being able to trade 24 hours a day, 5 days a week, you shouldn’t (Forex trading is not quite 24.7). You should only trade a forex pair when it’s active, and when you’ve got enough volume. Trading forex at weekends will see small volume. Take GBP/USD for example, there are specific hours where you have enough volatility to create profits that are likely to negate the bid price spread and commission costs.

"Forex" stands for foreign exchange and refers to the buying or selling of one currency in exchange for another. It's the most heavily traded market in the world because people, businesses, and countries all participate in it, and it's an easy market to get into without much capital. When you go on a trip and convert your U.S. dollars for euros, you're participating in the global foreign exchange market.

When trading in the forex market, you're buying or selling the currency of a particular country, relative to another currency. But there's no physical exchange of money from one party to another. That's what happens at a foreign exchange kiosk—think of a tourist visiting Times Square in New York City from Japan. He may be converting his physical yen to actual U.S. dollar cash (and may be charged a commission fee to do so) so he can spend his money while he's traveling. But in the world of electronic markets, traders are usually taking a position in a specific currency, with the hope that there will be some upward movement and strength in the currency they're buying (or weakness if they're selling) so they can make a profit. 
^ The total sum is 200% because each currency trade always involves a currency pair; one currency is sold (e.g. US$) and another bought (€). Therefore each trade is counted twice, once under the sold currency ($) and once under the bought currency (€). The percentages above are the percent of trades involving that currency regardless of whether it is bought or sold, e.g. the U.S. Dollar is bought or sold in 88% of all trades, whereas the Euro is bought or sold 32% of the time.
In the futures market, futures contracts are bought and sold based upon a standard size and settlement date on public commodities markets, such as the Chicago Mercantile Exchange. In the U.S., the National Futures Association regulates the futures market. Futures contracts have specific details, including the number of units being traded, delivery and settlement dates, and minimum price increments that cannot be customized. The exchange acts as a counterpart to the trader, providing clearance and settlement.