Your iPad running iOS 8.1 automatically locks itself when you press the "Sleep/Wake" button and when the device is not used for a certain period of time. When the screen locks, you must enter a passcode or use your fingerprint to unlock it in order to regain access to the device.
Unlocking the Screen
To unlock the screen, press the "Home" button or the "Sleep/Wake" button to wake it up. Slide your finger across the "Slide to Unlock" message at the bottom of the screen and follow the prompts to unlock the device using your passcode, Touch ID or alphanumeric password. Which option you're presented with varies depending on how security is configured on the device.
Changing Your Passcode
Your iPad's passcode is managed using the Settings app. To change it and its associated settings, open the Settings app, touch "General" and select "Passcode Lock." Depending on the version of iOS running on your iPad this menu item may be labeled "Touch ID & Passcode." On the passcode settings screen you can change your standard four-digit passcode. You can also set a more complicated alphanumeric passcode or set up the Touch ID feature, which unlocks your screen using your fingerprint. Keep in mind that even if you enable Touch ID, you will sometimes have to enter a passcode as well for added verification.
Modifying Passcode and Auto Lock Settings
The Passcode or Touch ID & Passcode section of the Settings app also enables you to customize other elements of the Lock Screen. For example, you can configure the iPad so its contents are wiped if someone enters the wrong passcode a certain number of times. On devices running iOS 8.1, you can configure the device so that six consecutive incorrect passcode entries locks the device for 1 minute. If you continue to get the passcode wrong, the device locks for 5 minutes.
To customize how long it takes for your screen to lock automatically, tap "General" in the Settings app and select "Auto-lock." You can choose 1 to 5 minutes or never.
Restoring an iPad’s Software
If you get locked out of your iPad, you need to restore its software to the factory settings. Unfortunately, this means all of your settings will be reset and your data, information and media will be erased from the device. Restore the iPad only as a last resort. Connect the device to a computer with which you've synced before. Open iTunes on the computer and select your iPad on the list of available devices. Click the "Summary" tab and select "Restore iPad." Follow the prompts to restore from either an iTunes or iCloud backup.
Entering Recovery Mode
If you can't access any backups in iTunes or the program won't let you proceed without entering the iPad's passcode, disconnect the iPad and hold down the "Sleep/Wake" button until the "Slide to Power Off" slider appears. Swipe the slider to turn the iPad off. Press and hold the "Home" button and plug the iPad back into your computer. Continue holding the "Home" button down until iTunes opens on your computer. If it doesn't open automatically, open it yourself. Click "OK" in iTunes to confirm you want to restore the device.