ipad

Type in the id and password of the account that it's locked to. If you can't remember your id : If you forgot your Apple ID - Apple Support . Or its password : If you forgot your Apple ID password - Apple Support

Or, and if you bought the iPad new (i.e. it's not second-hand), you could try going to an Apple Store (make a Genius Bar appointment if you do) or try contacting iTunes Support online (http://www.apple.com/support/itunes/ww) and see if they can remove the iPad from the 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