Music app's ringtone trimmer if you want to set only a part of the song as ringtone.
When you find the song that you want, tap
Drag the trim sliders to the part where you want the ringtone to begin and end.
For a more precise trimming, tap the left or right arrow buttons. Time markers indicate where you are on the song.
When you're done trimming, tap
Choose whether to set your trimmed song as your
Phone ringtone or
Tip: You can see your new ringtone in the phone settings. Slide the Notifications panel open, and then tap