iPhone 8 and iPhone 8 plus are latest version of iPhone available but unfortunately these devices are also facing many major issue. One such issue reported by many users us when iPhone 8 screen becomes unresponsive out of nowhere. When trying to tap an app icon on the home screen the phone was unresponsive. The screen of iPhone 8 became unresponsive. Force touch also does not work. No response to any swipes or presses or taps on the home screen. This is causing major issue as in iPhone 8 won’t be able to do a normal "slide to power off" Shut Down with the power key.
It is happening very frequently for some users like 4 times in 24 hours since purchase. The problem is sometimes easily seen while using 3d touch functionality in the home screen. Or when you try to send a photo -- screen freezes and won't accept command to message (or mail) photo. This happens 30-40% of the time. Below mentioned trouble shooting does not seems to help much.
a) Restoring phone does not work, b) hard reset does not work all the time, and c) getting a new phone does not fix it either.
Many users relate this issue to YouTube app downloaded, after the iPhone 8 plus has YouTune app this is when the touchscreen issues started for them.
As the device are on iOS 11 and the no other iPhone models like iPhone 7 and iPhone X has such frozen screen issue widely spread it could be an Apple hardware issue. You may try to replace your iPhone 8 at Apple store, just take Proof of purchase and identity and they will see you have Apple care and Replace the device as this seems to be hardware issues.
Since Apple has no solution, you don't have any solution, at this point anyway.
Any solution for the issue :
Since Apple has no solution, and seems to be hardware issue at the moment so at this point there is no known working fix but you may see below steps in case it helps to avoid iPhone 8 Phone Freez issue.
it might be an app that causes my phone to freez, I had to reset my phone and installed the apps I had one by one, and it started to freeze right after I installed a free message app, I delete it and my phone was fine again.
You may also try to do a force restart at the time you are facing iPhone 8 screen frozen issue, To do a hard reset in iPhone 8->Press the Vol up, Vol, down, then hold the power button till the phone restarted itself.