I want to sell my I pad 3 . How can I cncel my older Apple ID

FIrst, you would not cancel your AppleID or create a new one when you get a new device - use the same AppleID and your information, purchases and backups will be available to you on a new device.

However, you will need to remove your ICloud account from the device. First, make sure you have a backup either on iCloud or in iTunes. Go to Settings - iCloud. Turn off Find My IPhone/iPad . Sign out of the iCloud account completely, then under General - Reset, use "Erase all content and settings". The iPad should restart and prompt to be set up as a new device (when it reboots, it should not ask for your AppleID login).

Matt

See this Apple support article:

What to do before selling or giving away your iPhone, iPad, or iPod touch

...Found by searching Apple's Knowledge Base HERE.