Hello @KimK281 ,
At this time audio files are not a supported file type for sending in emails or storing in the Library. I've submitted your case to the engineers to review the request. If and when there's an update to this capability, they'll make sure to reach out.
In the meantime, I recommend hosting the sound file elsewhere - such as a cloud, audio hosting, or video hosting site - then link to the location of the audio like a regular hyperlink.