Apple Digital Masters (AKA ‘Mastered for iTunes’ or MFiT) are songs that have been mastered by a certified engineer following certain guidelines and best practices to guarantee a high quality result without clipping distortion during conversion to lossy formats of streaming.
Your music will be labeled as an “Apple Digital Master” in the Apple Music store which is a positive sign for many buyers and listeners to know that your masters are high quality and worth a listen. It is one of very few ways to differentiate your music from your competition. This can possibly help to increase your sales/streams (no guarantees of course) and open you up to a new market of audiophile listeners who seek out Hi-FI audio.
Only releases mastered by a certified engineer (such as me) are eligible to display the Apple Digital Masters badge (shown above) on their releases and marketing material.