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Deckle
Open a PDF

Flatten PDF

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Flatten PDF form fields into the page, so the filled-in values stay visible but can no longer be edited.

How to flatten a PDF form

  1. Choose a PDF that contains form fields.
  2. Wait for the field scan. It shows how many fields, appearances and pages it found.
  3. Press Flatten PDF.
  4. Download the flattened copy.

Options

No settings
Flatten PDF has nothing to configure. It works on every supported field in the file, and the button only starts once the scan has passed.
Field scan
Before anything is changed, Deckle reads the form and checks each field has a usable saved appearance. If a field cannot be flattened safely, the reason is shown and the button stays disabled.

What you get

  • One PDF named after the original with "(flattened)" added.
  • Each field's saved appearance is drawn onto its page, then the interactive field is removed.
  • Values can no longer be edited, ticked or cleared in a PDF reader.
  • Page links stay clickable. Pages and page sizes are unchanged.

Limits

  • Supported fields are text, checkbox, radio button, dropdown and list fields.
  • PDFs with XFA forms, signature fields or other field types are refused.
  • A field with no reliable saved appearance, or a hidden or rotated widget, blocks the run. Open and save the file in a PDF editor that writes appearances, then try again.
  • One PDF at a time.
  • Fields tied to optional-content layers are not flattened, because their visibility would be lost.
  • The page shows what was saved in the file. Deckle does not redraw fields from their values.

Check the result

Open the download and try clicking a field. It should not respond, and its value should look the same as before. Deckle checks that no form fields remain, that each saved appearance is on the page, that the pages still look the same and that links survive.

Questions

What does flattening a PDF do?

It turns form fields into ordinary page content. The values are kept as printed text and marks, but the fields are no longer interactive.

Why flatten a filled form?

So the values cannot be changed by mistake, and so every reader shows them the same way, including ones with weak form support.

Can I edit the form after flattening?

No, not in the flattened copy. Keep the original if you may need to change values later.

Why does Deckle say my PDF cannot be flattened safely?

The scan found something it cannot keep accurately, such as XFA data, a signature field or a field without a saved appearance. The message names the problem and what to do.

Does it flatten comments and annotations?

No. It flattens form fields only. Links stay interactive.

Is the PDF uploaded?

No. The form is scanned and flattened in your browser.

Can I fill the form and flatten it in one go?

Use two steps. Fill the fields with Fill PDF forms, then open the filled copy in Flatten PDF.

Will the text still be selectable after flattening?

The page text that was already there stays selectable. Deckle compares the text and the rendered pages with the original after saving.