In 2012 there was a lot of fuss over Apple’s MFiT program (Mastered for iTunes). Unfortunately they didn’t manage to get necessary information across to self-produced musicians as well as producers. Mastered for iTunes exists as two things:
Apple requires digital audio assets of high resolution so MFiT is considered to be unique. For example, 24-bit WAV files at a sample rate of the mix master source. Any contemporary specialized pro music mastering services engineer if he is qualified is familiar with these specifications. You can find some detailed information about them if you follow the link _http://www.apple.com/itunes/mastered-for-itunes/. Mastering engineers can provide their producers with the information about MfiT premasters.