Flatten a PDF — Lock Fillable Form Fields

What you can do

• •Flatten AcroForm fields into static page content
• •Remove leftover widget annotations
• •Keep the result uneditable as form fields
• •Run locally in your browser

How it works

1. 1

   Choose your PDF

   Select a PDF that contains fillable form fields.

2. 2

   Flatten fields

   The tool bakes AcroForm values into the page and drops leftover widgets on your device.

3. 3

   Download

   Save the flattened PDF file.

Common uses

• •Lock filled answers before emailing a form
• •Stop others from changing checkbox values
• •Make a filled PDF print more reliably
• •Share a snapshot of a completed application

Frequently asked questions

What does flattening a PDF do?

It converts fillable AcroForm fields into static page content and drops leftover annotation widgets. It does not rasterize freehand drawings that are already part of the page stream.

Why should I flatten a PDF?

Flattening prevents others from altering your filled data and helps the document display consistently across PDF viewers and printers.

Can a flattened PDF be un-flattened?

No. Once flattened, field values become part of the page content. Keep an unflattened copy if you need to edit it later.

Does it affect my signature or annotations?

A signature stamp added with Sign PDF is already drawn into the page, so it is unaffected. Flatten targets interactive form fields and the widget annotations left behind with them.

Will flattening make the file smaller?

Not usually. It changes how the content is stored rather than compressing it. Use Compress PDF if size is the goal.

Is this process private?

Yes. Flattening runs entirely on your device for this tool.

Related PDF tools

• Fill PDF Forms
• Sign PDF
• Protect PDF
• All PDF tools