I don’t have a Word document, can I convert my PDF to Word?
If you use the text select tool, you may be able to copy and paste the text from the PDF into a word document. You could also try using a service such as Online-Convert.com or Zamzar.com – they will sometimes work a little better, depending on the document.
If your book is appropriate, you can also use the Kindle Textbook Creator that allows you to directly sell your PDF as a Kindle book, but be aware that you may have a larger than necessary file size, your book may not be available on all devices, and readers may not have the customizability of their reading experience that they are accustomed to.