How do you create a MP3 on iMac?

To create an MP3 on an iMac, you can use the Music app (formerly iTunes). First, open the app and go to Preferences. Under the Files tab, select "Import Settings" and choose "MP3 Encoder" from the dropdown menu. Then, select the audio file you want to convert, go to the File menu, and choose "Convert" followed by "Create MP3 Version" to generate the MP3 file. The new MP3 will appear in your library alongside the original file.