It has been a common issue with Apple devices that sometimes they freeze and just show blank screen. In such cases, the device does not respond at all and wont even restart by pressing the Power Button.
The first thing to try is a simple device reset. Press and hold the ‘Power/Sleep/Wake’ button and the ‘Home’ button simultaneously for about 10-15 seconds. The iPad should then show the Apple logo and restart. The data on your device will remain as it is and should start working normally.
The above method has worked for me every time I face this issue.
In case, it doesn’t make your device to restart, then make sure the device has enough battery power. Plug-in the device to a power source and charge it for about 30-40 mins.
If still the device is not booting up/responding then you may need to contact the Apple service center.
Also check the below official Apple forum for resolution methods for blank screen issue-
Thanks for checking out !