Fantasy takes place in a fictional world, which makes the story fantastical. The main types of fantasy are high fantasy (set in a fantasy world with different creatures, like the Lord of the Rings), portal fantasy (where characters start in a normal world and go through a portal to a fantasy one, like The Wizard Of Oz or Alice in Wonderland), and quest fantasy (where the main character goes through a quest with fantastical things that happens during the quest, like Percy Jackson or Harry Potter).
There are also many other types of fantasy like Comic Fantasy, Epic Fantasy, and Sword and Sorcery, to name a few. But sometimes, fantasy as itself can be challenging to write. You may get stuck with problems like not having enough fantastical elements, making it something that you don’t want it to be or feeling like you are using all the fantasy elements in a fantasy book you like. In addition, fantasy can get very confusing for you and the reader.
What you want to do is get some really nice fantastical elements in. Now, you might be wondering: what is that? Fantastical elements are objects or people that can bring the world to life. For example, in Harry Potter, it is about witches and wizards. J.K. Rowling made sure to add in all of the elements that you need in witchcraft and wizardry such as potions and spells, while also adding things in like horcruxes. This really helps show the environment and setting.