Clearly, songwriting is when you write a song. I mean, the name pretty much sums it up.
However, currently the word songwriting implies professional songwriting. Popular songs started to be sold as sheet music in the 19th century. Later, they got played on the radio, put in movies and TV, and sold as records, tapes, CDs, and MP3s. Over time, they began to take on songwriting standards.
The songwriting standards covered various topics:
- How long should the song be?
- What form should you use?
- How do you write the lyrics?
- What rhyme scheme do you use?
- Who will it be sung to?
- Who will sing it?
- What instruments play it?
- What styles of music do you use?
As the standards of the profession evolved, listeners heard how the songs they liked were organized. When they started creating songs just for fun, they intuitively included these standards into their music and lyrics.
This means that writing a well crafted song involves learning how to write to the standards found in popular music in all its various forms. You may be a pro trying to make a living off your songs. Or you might be an amateur and just want to make your songs sound more like your favorite music. Either way, the craft remains.