Did your scan come out sideways? One click and it's done. The rotation applies to every page.
Use it when a document went into the scanner upside down or came out sideways, or when photos taken with a phone camera ended up the wrong way around after being converted to PDF.
Q. Can I rotate pages individually?
This tool rotates the whole document by the same angle. To rotate pages individually, use the rotate buttons on each page in Organize PDF pages.
Q. Does rotating reduce quality?
No. Nothing is redrawn as an image; only the PDF's rotation value changes, so the original quality stays exactly the same.