Syncing
We are unable to sync music from macbook to iPhone. How do we troubleshoot?
iPhone 5, iOS 9.3.2, syncing issues
Make sure iTunes is up to date on your Mac.
Launch iTunes. Then go to the iTunes menu bar, (top of your screen) click iTunes > Check for Updates
Sync your iPhone, iPad, or iPod touch with iTunes on your computer using USB - Apple Support
Or, if you are syncing via iCloud, check here > http://www.apple.com/icloud/setup/