Protect PDF vs Flatten PDF

Use /pdf-tools/flatten-pdf when you only need to convert interactive form fields into static content so the document is easier to share, archive, or print.

Use /pdf-tools/protect-pdf when you want the broader browser-side protection workflow: flatten the file, add visible protection marking, and prepare a more final-looking copy before sending it to someone else.

Flattening alone focuses on making form fields static. /pdf-tools/protect-pdf goes further by adding visible protection marking and positioning the result as a final-state sharing copy rather than just a flattened one.

That difference matters when the recipient should immediately recognize the file as a finalized document. If you only need stable content, flattening is often enough. If you also want visible deterrence, protection is the better fit.

Neither workflow gives you true password encryption, certificate-backed signing, or enterprise-grade permission controls. If you need open-password security or strict PDF permissions, move to a desktop or server-backed encryption workflow after preparation.

That is why /pdf-tools/protect-pdf should be understood as browser-side preparation, not as a replacement for full encrypted document security.

A common send-ready sequence is sign with /pdf-tools/sign-pdf, then choose between /pdf-tools/flatten-pdf or /pdf-tools/protect-pdf depending on whether you want plain flattening or visible protection, then finish with /pdf-tools/compress-pdf for email delivery.

If you want the broader context for email delivery, continue to /guides/how-to-prepare-pdf-for-email-delivery after choosing the right finalization step.