A song in a Facebook Reel can stick in your head for days. Facebook lets you tap the music label and follow the track inside the app, but it won't give you a file. To keep the song as audio you can play anywhere, you need to save the video's soundtrack. ICANDL does that from the video link.

Download the music as MP3

Open the video or Reel on Facebook, tap Share and choose Copy link.
Open the Facebook audio downloader.
Paste the link and tap Download.
Choose "Download Audio Only (MP3)".

The MP3 holds the whole soundtrack of the video. When the video is just a song over pictures or dancing, that's the music. The same steps work for Watch videos and normal video posts, as long as they're public.

What you get, and what you don't

The file is the sound as it plays in the video, nothing more. This matters for music:

Reels often use a short clip of a song. The MP3 is the same length as the video, not the full track.
If someone talks over the song, the voice is in the MP3 too. A plain download can't split voice and music, because Facebook delivers them as one soundtrack.
The audio comes at the quality Facebook stores. It's fine for listening, but it isn't a studio master.

If you want the whole song in good quality, find its name and get it from a music service.

Find the song's name

In a Reel, the music label at the bottom shows the track and artist when the creator picked it from Facebook's library. Tap it to open the song page.
Read the caption and the comments. Someone has usually asked already.
Play the MP3 near a song recognition app such as Shazam or Google's "Search a song" feature.

The same tricks work on Instagram; see how to find the song name from an Instagram Reel.

Make it a ringtone

If you want a few seconds of the track as your ringtone, the ringtone maker takes the same Facebook link, lets you pick a start and an end, and saves an MP3 for Android or an M4R for iPhone.

About rights

ICANDL doesn't host or store the files it processes. Music in Facebook videos is licensed for use on Facebook. Listening to your own copy is personal use; posting the song in your own videos or sharing the file is not covered, and Facebook or YouTube may mute or remove a video that uses it.

For the general audio steps see downloading audio from a Facebook Reel or video. The Hinglish version is Facebook video ka audio kaise download kare.