How Do You Write in a Book?

When it comes to paper books, I really struggle with writing in a book. But I just keep my iPad next to me and I add interesting words to my notes app. It can be something that I've never come across or it's a word I know, but I don't use very often. And yeah, I used to be a shame of it, you know? I used to feel like, oh, I'm not good enough. I can't read. Don't be. Because it is not a linear process necessarily. Specifically, I don't fiction because you have so many ideas in that book."