If some areas of the screen are unresponsive to touch - or input from an Apple Pencil - the iPad may have a fault. If purchased directly from Apple, you have 14-days within which you may unconditionally return the iPad for exchange or refund. If the opportunity exists, you would be well advised to make use of this facility while you are able to do so.
After expiry of 14-days, or if purchased from another retailer, you’ll need to explore your available options under your warranty.
You would be well advised to seek assistance directly from from Apple Support. You can contact the Support Team using the Get Support link at top-right of this page. Alternatively, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:
https://apps.apple.com/gb/app/apple-support/id1130498044
You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) where the technicians will be able to test and assess your iPad - and you’ll be able to explore your available options:
Genius Bar Reservation and Apple Support Options - Apple