Create a ringtone from a song on itunes 12.5
Hope this could be helpful.
1. Open itunes on your computer.
2. Select the song you want to use as a ringtone from your itunes library.
3. Right click then "Get Info".
In the get info window, select the Options tab and change the start and
stop time on the part of the song that you want to use as a ringtone. The
length of the tone should not be more than 30 seconds. After setting the
start and stop time click OK.
4. Click File/Convert/Create MP3 version.
The new mp3 version will be shown in the "Recently Added" folder playlist.
Copy or Drag it into your desktop.
5. Use a "Audio Converter" to convert the song on your desktop to "m4a format".
I use "Music Converter Pro" which you can download for free on the Appstore
or you can use any software as long as you can convert the song into m4a format.
6. Once the mp3 version has been converted into m4a. Select the m4a version and
rename the extension file from .m4a to .m4r. Changing it to m4r makes the file
format into a ringtone.
7. Drag the song into the itunes Tone Library.
8. Connect your iphone to itunes.
9. Select the “Tones” tab from the iPhone section.
Under the Tones section, select “Sync All Tones” and then click on the “Sync” buttonat the bottom of the iTunes.When your iPhone is done syncing, the new ringtones can be found in your Settings app on your device.Go to Settings> Sounds> Ringtone and select your new tone. These can also be used as text message tones, so you can really let your creativity shine.
iPhone 5s, iOS 10.1