How to remove metadata from a PDF

What is PDF metadata?

Metadata is information stored about a document rather than on its pages. You don't see it while reading, but anyone who receives the file can look at it. It usually includes:

• Document properties: title, author, subject, keywords, and the dates the file was created and changed.
• The software used to create the PDF, which can also hint at the company or the computer it came from.
• XMP metadata: a second, more detailed copy of the properties, which some tools don't update when the visible properties are changed.
• Other hidden data: attachments, scripts, content on hidden layers, page thumbnails and earlier saves still inside the file.

Why remove it before sharing

• The author field can show a name or user account you didn't mean to share.
• The title can be left over from an earlier draft, or from a document made for a different client.
• Earlier saves can keep content you deleted: many PDF editors add changes to the end of the file instead of rewriting it, so the old version can still be inside.
• Attachments and scripts can carry files or code the recipient doesn't need.
• Comments and review notes may reveal internal discussions about the document.

How to see a PDF's metadata

These show the main properties. They don't show attachments hidden inside the file, XMP metadata or earlier saves, which is why a dedicated tool is more thorough than checking by hand.

• Adobe Acrobat Reader: choose File, then Properties (Ctrl+D on Windows, Cmd+D on a Mac).
• Preview on a Mac: choose Tools, then Show Inspector.
• Chrome: open the PDF, click the menu at the top right of the viewer and choose Document properties.
• Firefox: open the PDF, open the viewer's tools menu (the double arrow at the top right) and choose Document Properties.

How to remove metadata from a PDF in PDFZyro

1. 1Open Remove hidden data on the Home page and choose the PDF from your documents, or upload it.
2. 2Check what's always removed: document properties (title, author, dates), XMP metadata, attachments, JavaScript and automatic actions, content in hidden layers, page thumbnails, other applications' private data, unused objects and earlier saves still inside the file.
3. 3Under Also remove, tick Comments and markup, Bookmarks or Links if the document should be just its pages.
4. 4For Form fields, choose to keep them, flatten them into the pages (the values stay visible) or remove them.
5. 5Click Remove hidden data. When it's done, a list shows everything that was removed.
6. 6The clean copy is saved as a new version, and the previous version stays in the version history. Download the clean PDF and share it.

What removing metadata doesn't do

• It doesn't change what's on the pages. Names, numbers or other details you can see in the text need redaction.
• It removes digital signatures, because cleaning changes the file. Clean the document before it's signed, not after.
• It only cleans the copy you share. Copies you've already sent, and the earlier version in your history, still have their metadata.

Other ways to remove PDF metadata

• Adobe Acrobat: the paid version can remove hidden information or sanitize a document from its redaction tools. The free Reader can't.
• Microsoft Word: before saving as PDF, use Inspect Document (File, Info, Check for Issues) to remove properties from the Word file, and in the PDF save options, untick Document properties.
• Editing the properties by hand: changing the title or author in a PDF editor only replaces what's in those fields. XMP metadata, attachments and earlier saves can stay, so a tool that removes hidden data is safer.

A short checklist before sharing a PDF

• Redact anything visible that the recipient shouldn't see.
• Remove hidden data, including comments if they're internal.
• Open the clean copy in a different reader and check its properties.
• Protect the file with a password if it's confidential, and send the password separately.