If you're unable to uncheck Read Only in the Folder and files on Windows 11/10, use attrib command. More solutions have been ...
Visual redaction instead of true removal. The most common method is to place a black box over sensitive text in a PDF or Word file. It looks secure, but the text layer underneath is still there.
Step-by-step instructions for creating PDFs from any file type, including methods for merging, compressing and password-protecting PDF documents securely.