Thanks for using Apple Support Communities. First I'd like to say congrats on your new iPhone 8. And I also can see from your post that you're unable to see iCloud Music Library as an option when you go into your Settings for your iPhone 8. This feature can be a great supplement for the Music App and I want to help make sure your device is working as expected. When you setup your iPhone, did you setup from a previous backup? Are you signed into your device with your Apple ID? Are you an Apple Music member?
The following links below can offer some help with this.
Turn on iCloud Music Library
Access your music collection on all of your devices with Apple Music