It's very profitable but risky as well. Without proper caution, a trader could loose an entire investment on a single trade.
Forex trading is basically exchange, the monetary engagement of buying and selling of currencies in major and minor pairs, stocks, commodities, indices, etc. Just like the common market where traders buy products on a certain amount and sell at a higher amount, forex trades on the same principles. Let's say you're trading a major pair of EUR/USD, you'd want to buy Euro against the dollar at a certain prize with the hopes of selling back at a certain higher price over a set period of time, in order to make a profit. The process also works the other way around.
However, forex trading in reality isn't as easy as buying and selling as it involves predicting real-time price movements, do not be deceived by those commercials. It takes a lot of time to understand the whole process, am talking about learning to work with trading instruments, understanding the different instruments used for trading and also learning how to read such instruments in order to be able to predict constant price movements which can be affected by many factors like government policies and most importantly, economic factors.
Personally, I enjoy trading, but not forest. I do most of my tradings around binary options. It's quiet similar with forex, but options affords quicker times for placing and execution of trades. In options, you choose to predict the rise and fall of prices within minutes. I'll recommend a beginner trader starts with options as it's a bit less complicated than forex trading.