Setting music as a ringtone on your Motorola Droid RAZR smartphone is easy with these steps.
Note: This tutorial assumes you have transferred music to your phone.
1. From a home screen, tap Apps and open the Music app.
2. Select a song to play.
3. From the Now Playing screen, tap Menu > Use as Ringtone.
The song you selected is now set as the default ringtone on your Droid RAZR.