I have an Apple subscription. My iPhone 12 Pro has lots of music that I copied from my old cds. I would like to sync my music libraries between the Mac and the iPhone but I'm worried that I'll lose all the transferred music files that have been stored on the iPhone. Will that happen?
iPhone 12 Pro
Turn on Sync Library on the phone (as described in Use Sync Library with your Apple Music subscription - Apple Support) and merge the content of the phone with your iCloud Music Library. Turn on Sync Library in Music on your computer, which will merge the local library with what you now have in the cloud. Download any matched or uploaded content to the computer and back up the whole library. See also If songs are missing from your music library after you turn on Sync Library - Apple Support.
For those that don't have/want an Apple Music subscription an alternative approach is given in Recover your iTunes library from your iPod or iOS device - Apple Community.
tt2
Turn on Sync Library on the phone (as described in Use Sync Library with your Apple Music subscription - Apple Support) and merge the content of the phone with your iCloud Music Library. Turn on Sync Library in Music on your computer, which will merge the local library with what you now have in the cloud. Download any matched or uploaded content to the computer and back up the whole library. See also If songs are missing from your music library after you turn on Sync Library - Apple Support.
For those that don't have/want an Apple Music subscription an alternative approach is given in Recover your iTunes library from your iPod or iOS device - Apple Community.
tt2
Transferring music from iPhone to Mac laptop
