How to share my music with my other phones
How do I share my music on my main phone iPhone 13 to my second line iPhone 12
Question marked as
To sync music between 2 iPhones entails a subscription to Apple Music.
You can sync from computer to iPhones: Sync your iPhone, iPad or iPod using your computer – Apple Support (AU)
If the music was purchased from the iTunes Store it can be downloaded on the other phone.