I have an eBook available on my website that is only readable online from the website (the data is in MySQL).
How do I make it downloadable for use on mobile devices offline (or for any other device)? What is the most common filetype used on mobile devices in which I would have to convert my eBook to?
I would also like people to also be able to copy this file onto flash drives so they can open it up and read it anywhere, including on mobile devices, and also spread the book around. I don’t know much about this topic, so please let me know what the standard procedure is for this.
The easiest way, perhaps, is to convert it to a PDF format, as they work across many devices. PDFs are a bit clunky, though, and don’t adapt well to screen sizes. The .epub format is a major ebook format these days, with many devices having apps for reading those. There are other formats like .mobi for Kindle-like devices, but .epub is the standard ebook format.
It’s probably not going to be straightforward to convert your site to any of these formats, but there is software that helps with this—such as DocBook, Pandoc, InDesign, Calibre, Habitat, Sigil, iBooksAuthor and Pages. There are some online tools, too, like Google Drive, Booktype, 2epub and dotebup.
An easier alternative to all this is just to make a static website, put it in a folder, zip it up and let people download that and view it in their browser like the online version. That will only be useful for desktop/laptop computers, though.