Where do i find ringtones on my iphone

Go to Settings on your iPhone. Choose Sounds & Haptics, and you can find Ringtone and Text Tone under SOUNDS AND VIBRATION PATTERNS. Click Ringtone to enter a new page where you can find a ringtone list containing all detectable iPhone ringtones.

Default ringtones are usually stored in /system/media/audio/ringtones . You might be able to access this location using a file manager.

Connect iPhone to computer and run iTunes, select "Tones" under "On My Device". Drag the "Tone" folder you just found and move onto "Tones" category in iTunes. Click "sync" and then go to Settings -> Sounds -> Ringtone to check if the custom ringtone is now set back.