The music industry is one of the most "closed off" but also "wide open" industries
It is VERY hard (understatement!) to break in to and the majority of opportunities are taken up by those already in the industry
HOWEVER...
It is ALWAYS looking for "the next big thing" and the next hit song
IF (and that is a big if) you write a hit song the industry (and the stars) will come looking for you!
This is a bit simplistic as you still need to get your hit song to the write person (and it may pass through a load that say "no" first) at the right time - but ALL publishing success comes from having potential HIT songs, which need to be "better" than what the established writers are producing
I think JESS' question about what a publisher does has been answered
May I ask some beginner questions about this strange thing called PUBLISHING. Like what to you pitch? Lyrics, songs, fully produced songs, etc? And do you pitch yourself as an artist or a songwriter or does it depend on what you want to get out of it?
An "artist" would pitch themselves to a record company
A songwriter would pitch their songs to a publisher - who will then use their contacts etc. to try and get an artist to record the song
Nowadays a pitch needs to be a "radio ready", fully produced track that stands up against any commercial track in the same genre
This usually means investing in your own home studio or committing to having your tracks recorded in a pro studio
But as I have said above - you really need to have a very strong "hit song" that you are prepared to invest in
A "guitar & vocal" sketch demo is unlikely to be listened to - even if it is a corker of a song
There are exceptions but the idea that "the song" will shine through and the listener/publisher will "imagine the production" or "come up with their own production" is a bit of a myth
They want to hear a track that sounds like a hit from the first listen - including the writing, performance, recording, production etc. etc.