Because the iPad is linked to your iTunes account, personal information and purchased digital content is potentially accessible to other users -- authorized and unauthorized. Before selling or giving an iPad to another user, or when you acquire a used iPad from a previous owner, it's prudent to erase all its content and settings, returning it to its factory default. This can also be a useful procedure to test the iPad when troubleshooting.
Launch the Settings application on the iPad by tapping its icon on the home screen.
Open the "General" page, followed by "Reset."
Press the "Erase All Content and Settings" button, followed by the red "Erase iPad" button to confirm. The iPad will reboot and display the Apple logo while its memory is cleared and its operating system is returned to its factory default status.