1. Open "itunes", select "File" - "Add file to library" in the menu bar.
2. Select the song to be the ringtone and click "Open" ".
3. The song will appear in "Music" in "Library". Right-click the song and select "Show Introduction".
4. Select "Options" and fill in the " "Start time" and "Stop time" (within 40 seconds), - "OK".
5. Right-click the song again and select "Create ACC version".
6 .A file with the same file name but within 40 seconds appears.
7. Right-click the newly created song, select "Show in Windows Explorer", and change the "m4a" format to " m4r", select "Yes" in the pop-up window.
8. Check: Find "Preferences" in "Edit" in the "itunes" menu bar and open it in "Common" - "Source" Tick ??"Ringtones" and then "OK"
9. You can see "Ringtones" in "Library" and open "Ringtones" to see whether your files have been transferred.
10. Then open "iphone" in "Devices", select "Ringtones", check the "Sync Ringtones" item, select "All Ringtones", or "Selected Ringtones", and then select "Synchronize", that's it.
11. After the "Ringtone" is successfully synchronized, the ringtone will appear in the phone's "Settings" - "Sounds" - "Ringtones" - "Customize". Just choose.