Fix Lock Screen of iPad
1. Reboot iPad
In some cases, you can try to force a shut down by pressing and holding both the Home and Power buttons at least 10 seconds until the iPad is turned off. After that, press the Power button to turn it on and try to unlock the lock screen again.
If you are using other devices, you can learn how to restart an iOS device.
iPad Pro: Press and quickly release the Volume Up button, and then the Volume Down button. And then press and hold the Power button until it retarts.
iPhone 8 and later: Press and quickly release the Volume Up button, and then the Volume Down button. And then press and hold the Side button until you see the Apple logo.
iPhone 7 or iPhone 7 Plus: Press and hold both the Power and Volume Down buttons for at least 10 seconds, until you see the Apple logo.
iPhone 6s and earlier, iPad, or iPod touch: Press and hold both the Home and the Power buttons for at least 10 seconds, until you see the Apple logo.
2. Update iPhone with iTunes
Updating the iOS software simply by connecting deivce to computer with iTunes and if there is an update, please update your device.
Choose device icon > Summary > Update after connected.
Confirm in the pop-up windows and wait.
You can also try to connect your iPad with iTunes and then restore from iTunes backup file. Or restore iPad from an iCloud backup if you have a backup file after that. Please remember to back up your device before restoring.
