Audacity is a free software, cross-platform digital audio editor and recording application. It is available for Windows, Mac-OS-X, Linux and BSD. wikipedia.org

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.

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

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

The guitar is a string instrument of the chordophone family constructed from wood and strung with either nylon or steel strings. 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

The piano is a musical instrument that is designed to be played by means of a keyboard. Widely used in classical and jazz music for solo performances, ensemble use, chamber music and accompaniment, the piano is also very popular as an aid to composing and rehearsal. wikipedia.org