As one of the most powerful online audio converter, FVC Free Audio Converter is absolutely the best free audio converter you can find. It enables you to convert all your audio/video files into MP3, WMA, AAC, WAV, AC3, AIFF, FLAC, etc. with ease. You are even allowed to convert a bunch of files at one time with no size limit. Besides, this audio converter is surprisingly easy to use.

Step 1.Use the link above to go to FVC Free Audio Converter. Click the Add Files to Convert button and select all the M4A files you want to convert.

Step 2.When the uploading process is done, click on the MP3 format. Then click the Convert button to start the conversion. After the conversion, you can enjoy the MP3 audio file on any devices or share it on YouTube, Facebook, etc.

How to Change M4A to MP3 Free with iTunes： https://www.free-videoconverter.net/mp3-converting/m4a-to-mp3/