PDF Privacy Checklist: 8 Things to Check Before You Share a Document

A PDF can hold more than what's visible on its pages: the author's name, text hidden under black boxes, earlier versions of edited content, attached files and comments. Most of the time that doesn't matter. When you're sending an ID scan, a payslip or a legal document, it's worth a two-minute check first.

1. Check the Document Properties

PDFs store metadata such as title, author, the software that made the file and when it was created. The author is often the account name on the computer that made it, and the title can be an old working file name. To see it, open File > Document Properties in Adobe Acrobat Reader, or Tools > Show Inspector in Preview on a Mac.

Before exporting from Microsoft Word, File > Info > Check for Issues > Inspect Document finds and removes personal information, comments and tracked changes, which would otherwise end up in the PDF.

2. Make Sure Black Boxes Actually Hide Something

This is the most common PDF privacy mistake. Drawing a black rectangle over text hides it on screen, but the text is still in the file underneath. Anyone can select it, copy it or find it with search. Test any redacted file: try to select or search for a word you covered. If you can, it isn't redacted.

3. Look for Comments, Layers and Hidden Content

Reviewers' comments, sticky notes and markups travel with the file and can be shown or hidden by the reader. Some PDFs have layers that can be switched on and off. Cropping a page in some editors only hides the edges from view; the content outside the crop box is still there. Open your viewer's comments and layers panels before sending.

4. Watch Out for Earlier Versions

Many PDF editors save changes by appending them to the file. Text you deleted, or an earlier filled-in value, can remain inside and be recovered with the right tools. Saving a fresh copy with Save As, or rebuilding the file (merging, splitting or extracting pages all create a new file), removes that history.

5. Remove Attachments You Didn't Mean to Include

PDFs can carry attached files that don't appear on any page, such as the spreadsheet a report was built from. Check your viewer's attachments or paperclip panel and remove anything that shouldn't go.

6. Rename the File

A file name like 'Jane_Smith_passport_scan.pdf' tells anyone who sees it in an inbox, a shared folder or a download list exactly what's inside. For sensitive files, a neutral name such as 'application-document-2.pdf' gives away less.

7. Send Only the Pages Needed

If someone needs one page of a statement, send one page. Extract the pages they need into a new PDF rather than covering up the rest. It's safer than hiding content, and the file is smaller too.

8. Think About Where You Process the File

Many free online PDF tools upload your file to their servers to compress or convert it, and keep it for anything from minutes to hours. That may be fine for a menu, but it's a real risk for an ID or a medical record. PDF Perfect processes files in your browser instead, so nothing is uploaded. You can test that yourself in 30 seconds, and our comparison of PDF tools that don't upload files shows how other popular tools handle retention.

Sending the File Safely

• If you password-protect a PDF, send the password by a different route, such as a text message, never in the same email.
• For very sensitive documents, a secure portal provided by the recipient is better than email.
• Delete compressed or edited copies from your downloads folder once they've been sent.