I stopped using Amazon a while back, but it was where I got all my books for a long time. I do thriftbooks mostly now, and try to buy directly from publishers when it’s a newer book, but I’m always interested in finding new spots to cop some sweet books.
I didn't see anything about converting from desktop directly but it's fine. I have all 3 of the other options working now. I did convert a .pdf to a .epub and send it but it messed up the formatting a ton, like put lines of bullets points below their respective bullets and such. I'd like to figure that out since I sometimes find books only as pdfs and they don't work very well on my 6" screen lol.