When you figure this out, writing becomes so much easier.
Before you start working on a new story, you first need figure out what your book is going to be about, character names/personalities, etc. You may even go so far as to map out each and every chapter of your book, crafting out every little detail. This is what it's like being a plotter.
Plotters know how everything is going to go, from start to finish, in their story. When Pantser's write, they typically don't follow an outline. They just open their computer and start writing.
I go over the pros and cons for each in the video below.
Once you figure out who you are as a writer, crafting new books becomes a little easier because you know how you're going to get started. Me, personally, I'm a plotter. I create a detailed outline (example shown in video) and plan out ALL my chapters, so that when it comes time for me to write, I already know what to cover.
I used to be a pantser, but I found it was harder for me to finish books when I never had the next chapter planned out, haha. Pantser/Plotter, one isn't better than the other, honestly. At the end of the day, don't try to force yourself into being either/or. You can be both. Just do what works for you.