It is not unusual for an iPad to become warm when being used - more so when using some types of iPad case. High screen brightness and/or CPU intensive Apps will also create more heat.
The key point is that whilst your iPad may become very warm in normal use, the iPad should not become uncomfortably hot to handle. If your iPad is becoming too hot to hold, you should take your iPad along to the Genius Bar at your local Apple Store - where the technicians can hands-on examine and test your iPad for faults:
Genius Bar Reservation and Apple Support Options - Apple
Should you need to do so, you can seek assistance directly from Apple Support using the Support link at top-right or bottom-left 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/app/apple-support/id1130498044