What does flattening a PDF form mean?

Flattening converts interactive form fields (like text boxes, checkboxes, and dropdowns) into static page elements, making the document non-editable.

Can I edit the form fields again after flattening?

No, flattening permanently removes the interactive AcroForm structure, turning the field values into permanent page content.

Why should I enable 'Update Appearances First'?

This option regenerates the visual appearance of the fields before flattening, ensuring that the text you entered is correctly rendered and visible in the final output.

What is the 'Remove Need Appearances' option?

It clears a flag in the PDF that tells PDF viewers to dynamically generate field appearances, preventing different viewers from altering how your static text looks.

Does this tool require uploading my files to a remote server?

No, the flattening process runs entirely in your web browser using client-side JavaScript, keeping your sensitive document data private.

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PDF Tools

PDF Form Flatten

Flatten a PDF form: bake field values into static content so the result is non-editable

Details

What this tool helps you do

Burns the current appearance of every AcroForm field into static page content, then removes the editable fields. This is the right tool when a form was filled elsewhere (e.g. in a viewer) and you only want to lock it down — no fill data needed. Pure-JS via pdf-lib.

Execution

Run this tool

Fill in the form, run the tool, and review the result in one place.

Prepared example runs

Click an example to fill the form automatically. File inputs still need an upload.

2 examples

Lock a filled form for distribution

Flattens a form that was filled in a viewer so the result is non-editable but visually identical.

{
  "type": "file",
  "filePath": "/public/samples/pdf/pdf-form-flatten-example1.pdf"
}

Flatten without altering appearances

Skips appearance regeneration (faster) when the source already has correct appearance streams.

{
  "type": "file",
  "filePath": "/public/samples/pdf/pdf-form-flatten-example2.pdf"
}

Inputs

Set the required fields, then run the tool.

4 options

FilesUpload source files for this workflow.1

PDF FilefileRequired

Single file max size: 100 MBSupported types: application/pdf

TogglesEnable or disable optional behavior.3

Update Appearances FirstcheckboxOptionalEnabled when checkedRegenerate appearance streams before flattening so values render correctlyRemove Need AppearancescheckboxOptionalEnabled when checkedClear the NeedAppearances flag so viewers don't regenerate appearancesKeep Form StructurecheckboxOptionalEnabled when checkedOnly update appearances but keep the AcroForm shell (rare)

Result

Ready for a run

Run the tool to preview files, text, structured data, or streamed output here.

Samples

PDF Form Flatten

What this tool helps you do

Run this tool

Prepared example runs

Inputs

Result

Examples that match this tool

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Prepared example runs

Inputs

Result

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Lock a Filled PDF Contract for Distribution

2. Flatten Form Fields Without Changing Layout

FAQ

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