1. One place to start is. Go there and check into the available writing jobs. What you’ll find is that there are a lot of them and they don’t pay enough to buy peanuts. So your education will be more along the lines of what’s out there for writers that pays something, even if not much. Then do your own research through other avenues to find similar jobs that actually pay enough to be worth doing. And you’ll find some of those jobs simply by going through what’s available on Freelancer and figuring out where they originated.
2. Another, more traditional way to start, is to figure out what kind of writing you want to do, then read, read, read in that area until you figure out what the publishers are looking for. Then close your eyes, hold your nose and jump in and write what you think they want to see. You probably won’t sell immediately but persistence pays.
3. The third way, depending on what you want to write, is to self-publish. It works but your competition will be millions of other writers, so the push in self-publishing is marketing. If you choose to go this route, first spend as much time as necessary learning how to market what you write because marketing starts long before anything is published and you’d best get busy.