Question: how to set a ringtone on iphone from itunes library?
Answer: Under the Tones section, select “Sync All Tones” and then click on the “Sync” button at the bottom of the iTunes screen. When your iPhone is done syncing, the new ringtones can be found in your Settings app on your device. Go to Settings > Sounds & Haptics > Ringtone, and select your new clip.