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I just published my first book, and it's available on both Amazon and iBooks. I also want to sell it on my website, but I'm still a little confused about the format options.
The original epub version will work fine in iBooks. You can get special iBooks formatting, but, as I understand it, that can only be done by Apple, and it can only be sold on iBooks.
I assume I need to save a version in the Kindle format for Kindle fans. I just downloaded an extension that lets you convert epubs to Kindle with Sigil.
So that's two formats - EPUB and KINDLE. Are there any other popular formats that people commonly sell on their websites?