How to reset an iPad to Factory Setting

If you still have your  iPad

Before you sell or give away your device, you should remove your personal information. You shouldn't manually delete your contacts, calendars, reminders, documents, photos, or any other iCloud information while you're signed in to iCloud with your Apple ID. This would delete your content from the iCloud servers and any of your devices signed in to iCloud.
On your device with iOS 10 or later, make sure that you sign out of iCloud before you erase your device.

Follow these steps:

1. If you paired an Apple Watch with your iPhone, unpair your Apple Watch.
2. Back up your device.
3. Sign out of iCloud and the iTunes & App Store. 
   • If you're using iOS 10.3 or later, tap Settings > [your name]. Scroll down and tap Sign Out. Enter your Apple ID password and tap Turn Off.
   • If you're using iOS 10.2 or earlier, tap Settings > iCloud > Sign Out. Tap Sign Out again, then tap Delete from My [device] and enter your Apple ID password. Then go to Settings > iTunes & App Store > Apple ID > Sign Out.
4. Go back to Settings and tap General > Reset > Erase All Content and Settings. If you turned on Find My iPhone, you might need to enter your Apple ID and password.
5. If asked for your device passcode or Restrictions passcode, enter it. Then tap Erase [device].
6. Contact your carrier for help transferring service to a new owner. If you aren't using a SIM card with your device, you can contact them to get help transferring service to the new owner.

When you erase your iPhone, iPad, or iPod touch, Find My iPhone and Activation Lock is turned off. 

How to reset an iPhone or iPad if you’ve got it at hand

Wiping you iOS device is easy, the only thing you’re going to need is your device passcode, Apple ID and Apple Password.

1. Go to Settings > General > Reset > Erase all Content and Settings.
2. An Erase iPhone/iPad warning box will now pop up. Click Erase and enter the device’s passcode and Apple ID info when prompted.
3. The device will then reset and, when completed, you’ll be presented with an iPhone/iPad as if it were straight out of the box.

How to reset an iPhone or iPad remotely

If you’ve lost your iPhone or iPad and want the peace of mind knowing any stored data will not be accessed, you can also remotely wipe your device.

1. Go to www.iCloud.com/#find > enter your Apple ID > click Find My iPhone.
2. Click on the option All Devices > chose the device you want to erase.
3. Click Erase iPhone/iPad.
4. Note that if you’ve lost your device, you can remotely play a sound on your iPhone/iPad to help you locate it.

How to reboot (soft reset) your iPhone or iPad

If your iOS device has crashed or stalled, and you only wish to reset (reboot) it, then you can do so easily without deleting any of your data by pressing and holding the Home and Power buttons simultaneously for 5-10 seconds.