What is the best way to convert jpg to?

Question

Djvu

It is necessary to convert scanned jpg files to any format (djvu, doc, docx, odt, pdf) - so that it is without loss of quality and compresses as much as possible.
now we use a utility for this (I work in pfr, a developer utility) - it converts to djvu, but at the same time it compresses the image very much, as a result, the text of the picture becomes unreadable

Answer 1

1) .jpg - already with loss of quality
2) what kind of files - text, images?
3) why not immediately scan to .pdf?