.m4a to .mp3 file conversion

I am working with a .m4a audiofile.
The .m4a is getting changed to .mp3,not by me, and neither vers. is playing in audacity 2.3.1.
I have a macbk pro, os10.12.6.
There appears to be sound in the file.but only a blip of noise.
There is a ffmeg library installed. i would include pix , is there an attachment icon in the form?
I want to edit the song, thx

I’m a Windows guy…

What does that mean?

Can you open and play the original file in Audacity?

You’re getting whatever format you export-as. It decompressed when you open it and Audacity doesn’t “remember” the format you imported.

If FFmpeg is correctly installed you should see an export format option of:
M4A (AAC) Files (FFmpeg)

I believe you need FFmpeg to open an M4A (you do on Windows) so I assume it’s correctly installed. But Audacity does need its own special version of FFmpeg.

Thx for getting bk to me.

It seems, google( maybe gmail) changed the file name from .m4a to .mp3. Audacity couldn’t play the file.
iTunes couldn’t play it either.
I don’t know if the format was actually changed .
I recorded the song on a moto phone .
When I uploaded the track to my hotmail , the .m4a wasn’t changed and audacity played it.
Same with iTunes.

I sent a follow-up email saying, thx, I fixed it. Got the song to open (to edit) in audacity