Dear Dhaval, Do not throw your money. First go and read some books. This is real serious advice. You will cry when you loose money. And believe me, all of us have lost enough Initially.
I assume you're asking about the desination url field that you see during ad creation. You enter the url you actually want visitors taken to in that box. if you're tracking this would be the place to enter your URL with your tracking codes appended to it.