my friend have that lucked by the icloud id and she forget the e-mail id , what can she do?

She could see if the can find her id : Recovering a forgotten iTunes Store account name - Apple Support and How to find your Apple ID - Apple Support

If she still can't find it, and if she was the original purchaser of the phone, she could try going to an Apple Store (make a Genius Bar appointment if she does) or try contacting iTunes Support online (http://www.apple.com/support/itunes/contact/) and see if they can remove the phone from her account - they are likely to want to see proof of ownership before they might help e.g. original receipt with the serial number on it