You can change the ringtone for incoming calls from the default to a custom one by following these steps:
- Open the Settings app on your iPhone.
- Go to Sounds >Ringtone to display your list of ringtones. (The built-in ringtones are listed under Standard; any ringtones you've synced with your device are listed under Custom.)
- Tap on the desired ringtone to select it.
Select a default ringtone for all phone calls.