Download the Apple Music Converter on your computer. Here sets Mac as example. More software review: https://drm-wizard.com/noteburner-itunes-drm-audio-converter-review.html
Click Add button to add the Apple Music. Select the songs that you would like to convert.
Go to setting panel, and choose output format as MP3.
Click the Convert button to start converting Apple Music to MP3 at 20X conversion speed. More solution: https://drm-wizard.com/best-apple-music-converter-to-mp3-review.html