Flatten PDF
Make filled forms, comments and stamps part of the page.
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Flatten PDF help
Make supported filled forms, comments or stamps part of the printed page. Choose which categories to flatten while keeping a separate original if you need to edit them later.
How to use Flatten PDF
- Choose a PDF with filled forms, comments or stamps.
- Select Form fields, Comments and marks, or Signatures and stamps to choose what becomes permanent page content.
- Select Flatten PDF; keep your original if you may need to edit these items later.
- Select Download flattened PDF and check that the answers and marks appear correctly.
Options explained
- Form fields
- Make supported filled-field appearances part of the page when the answers no longer need to be interactive.
- Comments and marks
- Flatten supported annotations into the page while preserving their visible appearance.
- Signatures and stamps
- Keep supported visible marks as page content; this does not preserve cryptographic signature validity.
- Save an edited copy. Its digital signature will no longer be valid.
- Shown for digitally signed input. Continue only when you want an edited copy; preserve the signed original for verification.
- Process all files
- Choose multiple inputs for flatten pdf. This runs the settings above separately for each file, shows individual results and failures, and offers Cancel file, Cancel all files and Download batch as ZIP. Check that page positions or form fields suit every input.
Limits and supported files
PDF documents. An opening password is required when the file needs one to be read.
Local tests used synthetic 10, 50, 100 and 200 MB PDFs containing large images. Chromium, Firefox and WebKit: completed 10, 50, 100, 200 MB.
Chromium, Firefox and WebKit: completed 50, 300, 1000 text pages.
Flatten PDF was tested on a 16 GB Mac with Chromium, Firefox and WebKit. These are observed examples, not guaranteed limits on your device. WebKit tests do not replace a check in Safari on your own device.
Up to 100 input files and 512 MB total; up to 200 output files or 512 MB. ZIPs over 128 MB need Chrome/Edge direct disk saving; use individual downloads in other browsers. The Workflow stress test completed 100 synthetic files in all three engines; this does not guarantee the same capacity for every conversion.
Questions
Does flattening make a PDF impossible to edit?
No. It removes the selected interactive items and places their saved appearance on the page. Other PDF editing may still change page content. It is not encryption or permanent redaction.
Will a digital signature remain valid?
Editing a signed PDF changes the signed document. Flattening may keep a signature’s visible appearance, but it does not preserve its cryptographic validity. Retain the signed original when signature verification matters.
Can I make filled form answers permanent?
Make supported filled-field appearances part of the page when the answers no longer need to be interactive.
Can I keep comments visible after flattening?
Flatten supported annotations into the page while preserving their visible appearance.
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