Although there are a number of ways to convert m4a to mp3 files, using iTunes to complete the conversion is recommended because it works for both Mac and Windows operating systems. To convert the file in iTunes, change the import settings, select the sound file, and then convert the file.Continue Reading
Open the Preferences menu in iTunes. Click the General button, and click Importing settings. Select mp3 from the list of formats listed in the Import menu. Click OK to save the settings.
In your song library, find the sound file that you want to convert. If you need to add the m4a file into iTunes, drag the file from its original location into the library pane in iTunes.
Click on the m4a file. Click File. Then, click Create New Version. Select Create MP3 version and the m4a file is converted to an mp3 file.