Then you need Scrivener, which is a wonderful writing program. Scrivener won’t write your book for you, but it will make writing it a lot easier. I’ve left Word behind and never looked back. My last two books have been written on Scrivener. And Scrivener's success has basically happened through word of mouth. I know so many authors who are using Scrivener - they are the ones who first turned me on to it.
You can try it out for free for 30 days. And if you participate in NaNoWriMo and write 50,000 words, you can get it for 50% off the already totally worth-it price of $39.95.
Try it out. You’ll be glad you did. I have zero connection to the company except that I am a really happy customer.