Scanned documents and photos of paper pages frequently end up sideways or upside down. Rotating a PDF fixes the orientation so the file reads correctly on screen and prints the right way up.
ColaPDF shows a thumbnail of every page so you can rotate just the pages that need it, in 90-degree steps, and leave the rest alone. The rotation is written into the document itself, so it stays correct wherever the PDF is opened.
Yes. Click individual page thumbnails to select them before applying rotation.
Yes. Use the "Select All" button then choose your rotation.
Yes, the rotation is baked into the output PDF.
No. Everything runs locally in your browser.