Q: Pad3,64gb,ios9.1.3,forget my iCloud and the password to complete start on after the update of my device.

Are you still logged into the account anywhere so that you can find your id ? Or do you have any of the accounts in your computer's iTunes library so that you can do 'get-info' on them in iTunes to look up the id ? If not try : If you forgot your Apple ID - Apple Support

If you can find it, to reset its password : http://iforgot.apple.com

If you still can't find it, and if you were the original purchaser of the iPad (i.e. it wasn’t bought used) then 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/contact/) 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