Everything you ever wanted to know about working with ringtones in iOS 7. Good stuff.
How to install and manage ringtones in iOS 7
Everything you ever wanted to know about working with ringtones in iOS 7. Good stuff.
You can also create custom tones in GarageBand and export them. (I haven’t tried with the latest GarageBand though.)
There is a clever method using garageband and toneconvert to download and add ringtones without iTunes, computer or jailbreak: https://www.youtube.com/watch?v=iL86_Jb7vxk
Sync ringtones to iPhone
How to delete ringtones from iPhone?
http://www.leawo.org/tutorial/how-to-delete-ringtones-from-iphone.html