Heating while charging

iPhones are built to release internal heat thru its casing. Unless you are getting a temperature warning pop up heat is typically very normal. Heat can happen because of many factors, so first make sure all apps and the iOS are up to date and take a look at If your iPhone or iPad gets too hot or too cold - Apple Support

Make sure that you're not leaving the iPhone on a soft surface (bed, sofa) while charging. That will make it harder to disappate the heat.

If your suggestion is to keep the phone in a fridge or air conditioner everytime it heats up… not a good one.. Phone should not get hot. Period… ONE PLUS & SAMSUNG are doing good job on this

Vinayiphone13 wrote:

If your suggestion is to keep the phone in a fridge or air conditioner everytime it heats up… not a good one..

Then it's a good thing I didn't make that suggestion, isn't it?

I made suggestions about best practices for charging a battery operated device. They apply to iPhones, laptops and yes, even Samsung phones (which have a very dubious battery history, by the way).