How do transfer mp3 files to iPhone that is configured with iCloud Music Library I subscribe to the Apple Music service.  When I connect my phone to my iMac and open iTunes on the mac and go to the Phone and select Music settings I get "iCloud Music Library is On"  iPhone can access your iCloud Music Library.  Songs can be downloaded and played via WiFi or cellular network.

The issue: On my Mac I have a playlist of mp3 files and I would like to get that playlist of my3 files onto my phone. In iTunes on the mac beside each mp3 file there there is an iCloud icon with a line through it indicating that "This item is not eligible for the iCloud Music Library"

So now I'm stumped on how to get this particular mp3 files from my personal library on my phone.
I ran into this myself, came across your question while seeking the answer, but have since figured it out.

https://support.apple.com/en-us/HT204926

The key is to enable iCloud Music Library under Edit > Preferences > General in iTunes.  That then enables the "Add to iCloud Music Library" right click option over albums and individual files.

Items you "add to iCloud Music Library" will then automatically appear in the Music app on your iOS devices.