Mastering, a form of audio post-production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master); the source from which all copies will be produced (via methods such as pressing, duplication or replication). wikipedia.org

Audio post production is the general term for all stages of production happening between the actual recording in a studio and the completion of a master recording. It involves, sound design, sound editing, audio mixing, and the addition of effects. wikipedia.org

"Narration is the act of telling a story, usually in some kind of chronological order."

Audio editing is the process of taking recorded sound and changing it directly on the recording medium (analog) or in RAM (digital). wikipedia.org

Voice-over is a production technique where a voice, that is not part of the narrative (non-diegetic), is used in a radio, television production, filmmaking or other medium.

Voice acting is the art of providing voices for animated characters (including those in feature films, television programs, animated short films, and video games) and radio and audio dramas and comedy, as well as doing voice-overs in radio and television commercials, audio dramas, dubbed foreign

An audio engineer is a specialist in a skilled trade that deals with the use of machinery and equipment for the recording, mixing and reproduction of sounds. wikipedia.org