Being an author is not an easy task; because you need money for different aspects of the book aside from writing. You need money to hire a professional editor to edit the book and you also need money to get the book published, especially if you intend to do self-publishing as opposed to traditional publishing.

So, to that effect, here are some ways you can get funding for your book:

Through donations: You can ask for donations from your friends and family, by telling them about your book (the theme and some other interesting details) and the amount you would need to get it published.
Read more at; https://www.issacharprojects.com/get-funding-book/