Heating

Try and Force restart iPhone 8

Press and hold both the volume down button and the Sleep/Wake button at the same time. When the Apple logo appears, release both buttons. (DO NOT release Side Button when invited to Slide Power OFF). 

If the above does not resolve the issue then is the iPhone 8 too hot to touch? If it is too hot to touch then you should have your iPhone examined at the Apple Store or at an Authorized Service Center for diagnosis and resolution.

Also note that, Your iPhone 12 will get warm as it charges. It may even get hot at times depending on ambient conditions and the level of charge applied. All this is normal. If your iPhone gets too hot to operate then it will shut down as a safety precaution. If it has not shut down then it is not overheating and operating / charging normally.

Axel F.

aksel66 Said:

"Heating: My iphone 8 is heating so fast.What should i do?"

-------

Two Things:

I. Cool Down the iPhone

II. Clear Space

In Depth:

I. Cool Down the iPhone:

For a few hours, perform the following...

• Power Off: the iPhone for a bit
• Unplug: any Cables
• Place it: atop a Laptop Cooler
• Keep it in: an open space
• Keep it Out of: direct sunlight

II. Clear Space:

Having little empty space can heat things up. So, here is what to perform...

A. Clear Temporary Internet Files:

Clear your Temporary Internet Files(Cookies & Cache) of Safari:

• Cookies perform remembrance of certain site-entered data.
• Cache keeps a snapshot of the last time you visited a site.
• Go Here: Clear the History and Cookies from Safari on your iPhone, iPad, or iPod Touch - Apple Support

Also...

B. Clean TV and Music Libraries:

Remove all unneeded files from your TV and Music Libraries. Full-Movies take up 2-4GB typically, and a bunch of those would take up a load of storage, ideally. So, if you have any movies that are not needed, then delete them.

Also...

C. Clear "Other":

Clear the storages named "Other". It basically contains unnecessary files such as caches that are used for system ease of use - all of which gather over time: How to Clear "Other" in your iPhone's Storage - Use Backup - User Tips. Caches would be being used for remembrance of application use.