Basically, with Word, there are two ways to go:
- Almost no formatting (just what was supported in https://medium.com/@leanpub/writing-leanpub-books-in-word-95822292078a and the linked resources there, i.e. https://github.com/leanpub/sample-word-book-one-file/archive/master.zip). This can be used with Dropbox or with direct upload, and Leanpub will generate a PDF, EPUB and MOBI.
- Just save a PDF from Word and use our "Bring Your Own Book" tool to just upload that PDF for sale. This lets you format the PDF however you want, but Leanpub is not making the ebook for you--so you get no EPUB or MOBI file, and the PDF is just what you upload, with no Leanpub formatting.