The iPhone 8’s home “button” is actually a solid-state sensor, which also includes Touch ID (fingerprint recognition) capability.
'''Most replacement home buttons won’t work''', so check carefully before starting your repair. Your iPhone’s original home button is uniquely paired to the logic board at the factory—and without Apple’s proprietary calibration process, even a genuine replacement home button from another iPhone won’t work. To fix a broken home button, you should install a specially-made, [https://www.ifixit.com/Store/iPhone/iPhone-7-7-Plus-8-8-Plus-Replacement-Home-Button/IF332-079?o=1|universal-style home button]. Note that these replacements only work as a button; Touch ID will not function.
If you are only replacing a broken screen, you can use this guide to carefully remove and transfer your working original home button to a new screen, preserving all functions, including Touch ID.
During this procedure, to avoid accidentally straining or tearing the display cables, it's best to completely detach the display assembly before beginning repairs on the home/Touch ID sensor. But if you are comfortable doing so, you may skip the display assembly section of this guide and go straight to the home/Touch ID sensor section.
Remove, transfer, or replace the home button in an iPhone 8.