currency exchange offices

[killbillgr21]

Hello guys
I am new in the forum.I have some basic knowledge about forex.Although,I have an assignment to do for university and I need some help from the experts on this forum. My question is:where do the currency exchange offices supply money from? They sell on more expensive rates, so they need to get money with the current rate in stock market in order to make money from the spread.If you have any additional information I would like to tell me.
Please help me out

 

[Enivid]

Foreign exchange offices earn on spread. They buy cheaper and sell higher.

 

[killbillgr21]

Thank you for your answer.
I already know that, my question is there they get cheap money from..