First, let's say iPhone6 how to modify your own ringtones:
1 Enter the phone "settings", click "Sound". (pictured below)
2 Find the "sound" bar, where you can change the ring, small series here to "telephone ringtones" as an example, in the "Phone Ring" menu bar, we can replace the call when the vibration mode, you can change their favorite ring. Also, in addition to changing the ringtone, we can also change ringtones such as text messages, emails, calendar reminders, and so on. (pictured below)
after talking about how to change the phone with the set of ringtones, the following will introduce how to use IPhone6 to replace their favorite music for their own ringtones. because IPhone6 's ringtones can only support the M4R format, and itunes can do this, now to introduce the music file with itunes for the format of the music file conversion.
