If you are talking specifically about "publishing" well-formatted, reader-friendly ebooks, Amazon Kindle Publishing accepts the following formats:

Word ( .doc or .docx)
PDF ( .PDF files)
Text files ( .txt)
ePUB ( .epub)
Mobipocket (.mobi or .prc)
HTML (.html) and Rich Text Format (.rtf)

You will need to create your manuscripts using one of the above programs or use Kindle tools to publish.

If you were talking about "viewing" docs on Amazon Kindle, it pretty much renders everything (kindle fire) with varying degrees of compatibility. The best viewing experience is possible with ebooks published for Kindle itself. All other documents aren't as easy to view and read as the former.

I own an Amazon Kindle and as I can see it, I can pretty much read PDF documents, view and edit Microsoft word documents, etc.