Open iTunes.
Select "iTunes" and click "Preferences" if using a Mac. Select "Edit" and then click "Preferences" if using a PC.
Click on the "Import Settings" button.
Select the "MP3 Encoder" in the "Import Using" box. Then click "OK."
Click "OK" again to close iTunes preferences.
Right-click or control-click the song title of the MP4 that you would like to convert into MP3.
Click "Create MP3 Version." After doing so, an MP3 copy of the song will be created directly below the MP4 version.
Open Switch.
Click "Add Files" and select the MP4 music file that you would like to create a MP3 copy of.
Click "Browse" next to the "Output Folder" box to select where you would like the MP3 copy to be saved.
Click the "Output Format" box and select ".mp3".
Click "Convert" and a MP3 copy will be saved in the output folder you selected.