Hold the "Command" key and click the MP4 music files you want to convert to MP3 in order to highlight the files simultaneously. Then click "Advanced" and choose "Create MP3 Version.". When the conversion is complete, MP3 versions will appear below the original MP4 music files in your iTunes library.How do you transfer YouTube videos to MP3?
To convert a YouTube video to the MP3 format, use the free version of Any Video Converter to download the video by copying its Web address, add the downloaded file to the main window, select the MP3 format, and start the conversion process. If necessary, modify the audio settings of the output file before starting the conversion.