This informational page currently provides some notes on music composition education in general, and what categories of music composition education there are.
This article is in its first draft stage.
The following diagram sheds some light on the Songwriter vs. Composer discussion.
The diagram yields the result that composers can write songs, and although songwriters are thereby composers, not all songwriters can "do" everything that composers "do." It is not certain that a songwriter can create an arrangement of a song, however, it is fairly certain that a composer will be able to do so. It is not certain that a songwriter can write for anything but a "band" type of setting. A composer can write for many different types of instrument combinations. Song authors belong between songwriters and lyricists.
If you are a song author and would like to upgrade your knowledge to become a songwriter, I invite you to purchase my eBook "How to Write Your Songs Down."