What happens if I buy/sell in Forex?

[Gtrade]

It's not an important thing to know in technical analysis but I'm curious to know what happens behind a buy or a sell in forex...for example if I buy a stock I buy a piece of a company, if I buy GBPUSD I exchange dollars with pounds, but what does it mean if I don't have dollars but only euro on my account? I mean what happens on the broker side?

[Marco vd Heijden]

This can be many things depending on what you are trading.

For example if it's a CFD or Contract for Difference they you are not exchanging dollars with pounds, but a contract that you think a currency will appreciate or depreciate in value over time.

There are many situations and parameters so likewise many different things can happen on the other side.

You can find info about this on your brokers website.