What M4P really is
M4P is an AAC file extension, created by Apple, that protects its content with Digital Rights Management technology known as DRM. You can find these types of audio files after downloading music from the iTunes Store.
They can easily reproduce on any Apple device, but when it comes to non-Apple ones, things are a bit different. If you want to listen to songs from iTunes on your Windows computer, you have to convert M4P to MP3 first. After that, you’re free to enjoy your favorite music.