I tried to create a Ringtone for my iPhone using the Library Tools>Ringtone. It did not work. After some Googling I found out why.
The Apple iPhone (mine is a 6s) requires a ringtone in the format of .m4r that is a normal m4a where you can just change the file extension from a "m4a" to a "m4r" in windows explorer>file rename.
MC creates its ringtone as an mp3.
I suggest, as a feature enhancement, the MC give Users the section of "create Ringtone for iPhone" where it then outputs the correct .m4r file, and possibly "create ringtone for android" (if that ringtone uses a different format).
ADDITIONAL: Just to add, the full process is - use MC to create the mp3 (ringtone) which creates a file (from your audio file) small enough to become a ringtone. Then import that mp3 file into "iTunes" where you use their convert feature to "create AAC version". BTW ITunes has a "create iPhone ringtone" option but that option is grayed out (maybe need to start with m4a to use that conversion). That creates the m4a file. Then you change that file extension to m4r using Windows Explorer and copy it to your phone (via iTunes). It's multi-step process that could be a lot easier.