How to use a Voice Memo as a ringtone on the iPhone

You need to use terminal or SSH.

The voice memos are located in this folder as .m4a files.
/private/var/mobile/Media/Recordings

My ringtones are located in this folder as .m4r files. (Is this folder different for everyone?)
/private/var/stash/Ringtones.z8OJCu

Copy the m4a files to the ringtone folder and rename them as m4r. It worked but I might look for a GUI file manager next time.