Re: changing a file extension
See if this still works: https://www.idownloadblog.com/2013/05/16/how-to-create-ringtones-in-itunes/
Brian - Windows 10 Home, 64-Bit, Version 1809, Build 17763
Explanations exist; they have existed for all time; there is always a well-known solution to every human problem — neat, plausible, and wrong.
~ H.L. Mencken, AKA The Sage of Baltimore