It is not unusual for an iPad to become warm when being used or during charging - more so when using some types of iPad case. High screen brightness and/or CPU intensive Apps will add to the generation of heat.
The key point is that whilst your iPad may become very warm while charging and 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.
Your iPad uses USB PD (Power Delivery) to actively negotiate charging power (i.e., charging voltage and current) when charged from a compatible power source or Power Adapter - and will adapt the iPads battery charging as required. Temperature and battery condition will influence the charging algorithm, which itself may differ between charging cycles.
Also note that the USB-C charging cable is an "active" component - as the cable incorporates unseen electronic components within the USB-C plugs. A faulty or damaged cable can adversely affect charging performance.
Troubleshooting
As a basic troubleshooting step, if you are able, consider swapping the Power Adapter and charging cable - one at a time - in an attempt to isolate a possible cause. You should note that simply disconnecting and reconnecting these items to your iPad may cause USB PD to renegotiate charging parameters - and in so doing clear a perceived issue.
If the issue cannot be cleared, try a forced-restart of your iPad - as this will often clear an isolated software issue:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.
If the problem persists after performing the restart, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:
How to back up your iPhone, iPad, and iPod touch - Apple Support
When you are happy to proceed, you can perform the reset from iPad settings:
Settings > General > Transfer or Reset iPad > Reset > Reset All Settings
If the problem still doesn’t clear, the next step is to reset the iPad to factory settings:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Otherwise, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively and perhaps easier, 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
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 can explore your available options:
Genius Bar Reservation and Apple Support Options - Apple
