RE: Repair of Android Devices
Your question is kind of ambiguous so I'll try to answer the most common scenarios.
If you bricked it there's nothing much you can do.
If you broke the screen, you can order one online and replace it yourself, or you can have somebody at a shop replace it.
If you damaged it's innards so to speak, your phone is not worth much anymore, your best bet is to try and sell it on ebay.