How to Set Any Apple Music Song as Your Alarm on iPhone
1. Open Apple Music and add the song to your library. Search for the song, tap the small ellipses off to the right of the song, and then tap Add to My Music.
2. Exit out of Apple Music and open up the Clock app, and go to the Alarm tab at the bottom.
3. Add or edit an alarm by tapping on the + icon or Edit, respectively. Tap on Sound and under the Songs section, select Pick a song.
4. Navigate to the song and select it. At that point, the song will now be used as your alarm when it goes off in the mornings.