One of the main goals is to have consistent levels throughout the whole album so the listener doesn't have to ever adjust the volume. Always respecting the original dynamics.
Music always sounds different in every playback device. Mastering will take care of finding the sweet spot where it will perform best in all platforms.
Using extremely transparent tools and tricks, your mix will still preserve its character while meeting the standards of a professional production.
This is the very final step where all the files get organized and ready to be released in the platform of your choice. This includes embedding metadata, PQ codes, conversions, and any other accommodations.