A clear answer. Here’s how.
Sets each selected page’s crop box so viewers show a smaller area, measuring margins from the edges as the page appears, including pages that are rotated. The page contents are not changed or removed: text and images outside the crop box remain in the file and can be recovered, so cropping is not a way to hide or delete private information (use the redaction tool). Because some viewers and printers use the media box instead, check the result in the program you will use. Up to 30 MB per file. Password-protected PDFs are not supported. Files are read and changed in this browser only and are never uploaded.