1. Make the ringtone file
- Open Ringtone Maker and drop in the song, as MP3, M4A, WAV or most other formats.
- Drag across the waveform to choose up to 40 seconds, and click Play selection to check it.
- Keep iPhone ringtone (M4R) and click Cut. You get an .m4r file.
2. Put it on the iPhone
- Mac: connect the iPhone with a cable, select it in the Finder sidebar, and drag the .m4r file onto the iPhone's General tab.
- Windows: in the Apple Devices app or iTunes, select the iPhone and drag the .m4r file onto it.
3. Choose it
On the iPhone, go to Settings → Sounds & Haptics → Ringtone. Your ringtone is at the top of the list. You can also give a contact their own ringtone from the contact's Edit screen.
Why 40 seconds?
The iPhone refuses ringtones longer than 40 seconds. For text tones, keep it to a few seconds.
Android
Choose MP3 instead of M4R, copy the file to the phone and pick it in Settings → Sound, or set it from your music or files app.