Check whether all pages need the same turn
A PDF containing only sideways scans is a good fit for one rotation applied throughout. A document with mixed orientations needs more care because a turn that fixes one page may make another wrong. This workspace does not offer individual page selection for rotation.
Example: correct a consistently sideways scan
If every page needs a quarter-turn clockwise, choose 90 degrees and download the result. If it needs a quarter-turn the other way, choose 270 degrees clockwise. Check at least the first, middle and final pages. Existing page rotation is included, so judge the saved result rather than assuming every source starts at zero.
Distinguish page rotation from editing the artwork
Rotating a page changes its orientation; it does not move individual pictures, straighten a slightly tilted scan or change portrait content into a redesigned landscape layout. Small scanning skews need a deskew or image-editing tool. Keep the original when you are uncertain which turn produces the intended reading direction.