How to convert Music files to MP3 in iTunes without using the "Preferences" Option

I am trying to convert some music files back to MP3 in my iTunes so I can email them. In video tutorials I am instructed to open iTunes and click "Music" on the toolbar, then click "Preferences" in the dropdown menu. However, the "Preferences" option does not appear. Is there a way to find it? If not, is there an alternate way to convert files?

[Re-Titled by Moderator]