How rotating works here

Add a PDF and every page appears as a thumbnail. Click a page to turn it a quarter turn clockwise, or use the two buttons to turn every page at once, then apply and download the new file. Rotating updates each page's orientation setting inside the document; the pages themselves are not re-rendered, so quality is untouched and text stays selectable. The whole job runs in your browser and your file is never uploaded.

Good to know

Perfect for scans that came in sideways or upside down.
Rotating is lossless and reversible: turn a page back and you are exactly where you started.
To pull pages out instead of turning them, use Split PDF.
To shrink a big scan after straightening it, use Compress PDF.