I have a iPad it becomes hot when I play PUBG mobile

It is not unusual for an iPad to become warm (or very warm) when being used - more so when using some types of iPad case. High screen brightness and/or CPU intensive Apps - such as graphics intensive games - 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 examine and test your iPad for faults.

Genius Bar Reservation and Apple Support Options - Apple