Is there a way to convert .mp3 audio files to .m4p format.
Converting MP3 Audio Files directly to iTunes Music Store Audio Files (.mp3 to .m4p conversion) should be possible and straightforward, even though it is quite redundant. The M4P file type is typically used for DRM protected music purchased from the iTunes store, and so it makes much more sense to work with the MP3 format.
Use an audio editing software or (online) conversion tool, such as Helium Music Manager or MediaMonkey, which should allow users to import MP3 audio files and export them in M4P format.
A music library management program
A digital media player and library