Use a web ringtone site so you avoid iTunes and GarageBand.
- On your iPhone, open Safari.
- Go to mp3cut.net or mp3cutter.com.
- Upload your song, trim 20–30 seconds, export as m4r if offered, mp3 if not.
- Download the file, then share it to the “Ringtones: Maker” or “Ringtones for iPhone!” app from the App Store.
- Follow the app steps to install via a config profile in Settings.
You get the ringtone with fewer steps and no computer.