Most don't have the faintest notion what it involves. There are a few things to understand about this world.
Now to publication, and we'll start with traditional publishing. First and foremost, understand that publishing is a business. It exists to make money for the publisher.
Plus, in SA, a bestseller is regarded as 3000 copies, most authors are delighted if they sell around 1000, and you earn about R8-10 per copy as an author.
Writing for the international maker requires finding a good agent first, and then hoping they can sell your book to a publisher. And even then, it could bomb.
And even if you go the e-book route, you will need someone to design the cover, edit the text, lay it out and format it, all of which costs money, if you want something with a professional finish that is well done.
Hard copies = printing.
Are you up for that?
And you not only have to produce those words, they have to sustain a reader's attention. Fiction or non-fiction, you have to tell a story.
And you have to craft every sentence. What do you leave out? What do you include? What senses will you employ to evoke setting, emotion?