hi,
what is the forex trading .and how can use in market for profite.
Hi John456, Your question is quite interesting.However since its not a one answer question,
I will refer you to the Babypips school for some information and trading classes.
Grix
In the starting you must learn the basics of Forex trading using the Demo accounts. Demo accounts are a great way to see how the markets work and what are the things that you need to learn and practice well before you can start doing real trading 
Just go through Babypips school, that should help you get started.
I think you should spend the next few months reading a lot of information, here at Baby Pips and at other outlets which you can find by googling your question. You can find an answer to the first part in less than 10 minutes. Forex trading is the exchange of currencies. The second part of your question can take you years to have answered with a strong chance that you will never find the answer as most traders fail.