The PDF opens in the browser, on your device.
Rotate every page or just the ones that need it, by 90, 180 or 270 degrees.
The rotation is recorded in the file, not just in the view.
The file does not leave your device. Thirty-two tools out of thirty-eight.
Yes: it is written into the PDF page, so any reader honours it. That is different from rotating the view inside a viewer, which does not modify the file.
Yes. If only a few pages are crooked, point them out and leave the rest as they are; if the whole document is sideways, rotate the entire file in one step.
No: rotation is an attribute of the page, not a new rendering of the image. The content is not recompressed and stays identical.
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