Under US copyright law, copyright (literally, the right to make and sell copies) automatically vests in the creator the moment the expression of an idea is “fixed in a tangible medium” (in other words, the moment you write it down, type it or record it). With respect to music specifically, there are actually two copyrights: a copyright in the musical composition or song owned by the songwriter and a sound recording copyright in the sound of the recording owned by the recording artist (but usually transferred to the record company when a record deal is signed). It is important to remember that you own the copyright in your work the moment you write it down or record it, and you can only transfer those rights by signing a written agreement to transfer them. Therefore, you must be wary of any agreement you are asked to sign.