There are four options to create audio books.
1) By taking photo of the book from within the app
2) By uploading images
3)By uploading PDF
4)By uploading TXT files
5)By uploading DOCX
6)From WebPage Link
https://play.google.com/store/apps/details?id=com.suyam.instareader&hl=en_IN&gl=US
InstaReader creates audio books from photos of textbooks, PDF, TXT, DOCX and WebPages instantly and will read out the audiobooks. InstaReader is also specifically designed for visually challenged and people with learning difficulties to read independently without the help from readers.