Flatten a PDF's forms and annotations
Flatten a PDF's interactive form fields into permanent page content, so filled-in values can no longer be changed or extracted. Runs in your browser — useful as a last step before sending a completed or signed document.
Flatten PDF
burns form values into the page, then locks them
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How to Flatten PDF
- Add your PDF. Drag the file onto the drop zone. The number of fillable form fields found is shown.
- Check the field count. If the file has no interactive fields, there's nothing here to flatten — the tool tells you plainly rather than pretending to do something.
- Flatten. Click Flatten PDF to burn all current field values into the page content.
- Download. Save the flattened file. It looks identical but can no longer be edited.
Why flatten a completed form
An interactive PDF form stays interactive after you fill it in — the values you typed remain editable fields, not fixed content. That's convenient while you're working on it, and a liability once it's finished: anyone who receives the file can open it and change your answers, and some tools can extract the field data directly.
Flattening converts every field's current value into ordinary page content and removes the interactive layer. The document then behaves like any other PDF: what you see is permanent. This is the standard last step before submitting a completed application, sending a signed contract, or archiving a finished form.
This flattens forms, not annotations in general
The scope here is specifically a PDF's AcroForm fields — text boxes, checkboxes, dropdowns and radio groups. Comments, highlights and drawing annotations added by a PDF reader are a separate layer this tool does not touch.
If you've just used the Fill PDF Form tool and want the result locked immediately, that tool has a flatten option built in — this standalone version is for when you have an already-filled PDF from somewhere else and want to lock it after the fact.
Frequently asked questions
What does flattening actually do?
It converts each form field's current value into permanent page content and removes the interactive field itself. The document looks the same but can no longer be edited or have its field data extracted.
Can I undo a flatten?
No — once fields are converted to page content, the original interactive structure is gone. Keep a copy of the unflattened file if you might need to edit it again later.
My PDF has no form fields. What happens?
The tool tells you directly rather than producing a pointless "flattened" copy — there's nothing to flatten in a PDF with no interactive fields.
Is my file uploaded?
No. Flattening happens entirely in your browser, which matters since the documents people flatten are usually completed forms with personal or financial information already filled in.
Does this affect anything other than form fields?
No. Annotations like comments and highlights are untouched — only the AcroForm field layer is flattened.
Why would I flatten instead of just keeping the form as-is?
A flattened PDF can't have its answers silently changed by whoever opens it next, and its data can't be pulled out programmatically. For anything you're about to submit or sign, that's usually what you want.