iPhone 11 won't turn on

Start here: https://support.apple.com/en-gb/HT201412

Hello there !

That is  how you do a “hard reset”. See below:

Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• • Press and quickly release Volume UP button
  • Press and quickly release Volume DOWN button
  • Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

if this steps not work:

see this article please:

If your iPhone won't turn on or is frozen