How do you change the text style in an article?

I'm planning on writning fan fiction and to seperate my words with the fan fiction itself I want to write in another text style, but I don't know how to do it and what does html stand for?

I have two fan fictions planned, their titles seems like they're similar to each other, but they're about two different things so here are the stories (trying to be short here, but that's not easy even though I'm pretty good at explain a story pretty shortly what it is about, but it's hard to do it now since they're my own ideas though I've written the first one before in school, we where supposed to write our own fairytales):

The first one in plans is called Alexandra and the Swan and it's about a princess named Alexandra who has a friend that's from our world named Julia, they have been best friends their whole life, but one day Julia gets turned into a swan by a witch and Alexandra has to go to the mountains where the witch is living to get the wand, but on the way she meets Snow White and they become best friends.

The second one in plans is called Alexandra and the Disney princesses and it's about another Alexandra who is from our world that one day sees a fairy named Tinkerbell and she follows her and falls down a rabbithole and comes into a room with 10 doors, but only one key. She tries the key onto all doors, but only the last one can be opened and when she gets in there Tinkerbell explains that each of the princesses has dreams and that it's up to Alexandra to help each of them through their stories, only then will she get the rest of the keys that leads to the next story until she is at the last one!

So which one seems more interesting to you because I'm going to write both and I might put it up as a pick so that I can see which one you would like to read? I personally would like to start with the second one because I think it's exciting to look forward to since it's like a game.

Both are going to be in parts since they are going to be pretty long to write