A record producer is an individual working within the music industry, whose job is to oversee and manage the recording (i.e. "production") of an artist's music.

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

Singing is the act of producing musical sounds with the voice, and augments regular speech by the use of both tonality and rhythm. wikipedia.org

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

An arrangement of a musical composition is a reworking of a piece of music so that it can be played by a different instrument or combination of instruments from the original. wikipedia.org