how do i share my music to someone elses iphone

On your iPhone, iPad, or iPod touch

1. Go to Settings.
2. Tap your name, then tap Family Sharing.
3. Tap Add Member.
4. If your child doesn't have an Apple ID, tap Create an Account for a Child. But if your child already has an Apple ID, tap Invite People. ... 
5. Follow the onscreen instructions.

Set up Family Sharing - Apple Support

Use iTunes Match

To access your songs and playlists on other devices, turn on Sync Library on all of your devices. When you sign in with the Apple ID that you use with iTunes Match on your iPhone, iPad, iPod touch, Mac, or PC, you associate that device with your account and get access to your music library.

Subscribe to iTunes Match - Apple Support