If you already tried (to no avail) these steps:
- On an iPad with a Home button: Press and hold the top (power) button and the Home button at the same time. When the Apple logo appears, release both buttons.
- On other iPad models: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top (power) button. Only when the Apple logo appears (it might take 15-30 seconds), release that button (ignore all other screens that might appear).
If the issue persists, it might be a hardware problem (digitizer?), but we, just users like you cannot diagnose that kind of issue remotely, sorry.
I suggest that you make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> Apple – Location Selector. After checking it out, they'll give you all the available options.
Regards
Giulio
(*) You can do it: