These are the formats that Calibre supports...
https://manual.calibre-ebook.com/faq...ersion-to-from
rar and zip are not ebook formats, so you need to extract whatever are in the zip and rar files and convert them to ebooks.
But I believe you can add additional file extensions for Calibre to recognise. I've never needed to do that, so I don't know where that is done in Calibre.