It's the "next" version after the mp3, hence why it's M4A.
It's supposed to have better quality, I truly never notice the difference unless is too evident.
You don't hear a difference on a laptop or phone per sé but if you put it on a CD (lol) or listen to it in your car via your phone M4A files provide a much clearer and louder sound than MP3. I'm obsessed with having all my music in M4A.
How do I live? How do I breathe?
When you're not here I'm suffocating
I want to feel love, run through my blood
Tell me is this where I give it all up?
For you I have to risk it all
Cause the writing's on the wall