Back up your data with iCloud before you erase it
Back up your iPad to iCloud before erasing it:
Click the Settings icon.
Select your Apple ID from the top of the Settings page, and then iCloud from the right side of the screen.
Select iCloud backup.
Click Backup Now
After your backup is complete, check the date and time next to your last successful backup to make sure the backup completed successfully.
How do I erase iPad data
The most important part of preparing an iPad for sale is making sure all traces of identity are removed from it. Do not sell or give away an iPad without erasing the data.
Click the Settings icon.
Choose a routine.
Select Reset.
Click to erase all content and Settings.
Even if you recently backed up your iPad to iCloud, you may be prompted to take another backup or continue erasing
If you have enabled the password (unlock code), enter it in the next window.
Select “Erase” when the pop-up menu appears.
If you have restrictions enabled, enter your restriction password.
Verify erasure again. Select Erase again.
Depending on the version of iOS installed on the iPad, you may need to enter your Apple ID account password to remove it from the iPad. You need access to the Internet (via a Wi-Fi or cellular connection) to perform this step.
Looking for the Hello screen
When the erase and reset process begins, the screen goes blank for a few minutes as the iPad erases your data and reverts it to factory Settings. You may see a progress bar showing the status of the erase and reset process. When the iPad completes the process, you will see the Hello or Welcome Setup Assistant screen as if you were setting up the iPad for the first time.