Yes — use the Undo button before applying. Once you click Apply & download, the redactions are permanent in the downloaded file. Always keep your original.

Black boxes are drawn on top of the content. For maximum security, verify that text cannot be selected under the boxes in your PDF reader, and consider using dedicated redaction software for highly sensitive documents.

Yes — navigate pages and draw boxes on each one. All redactions across all pages are applied in a single download.

Never. Files are processed entirely in server memory and permanently discarded the moment your download completes.