Flatten PDF
Bake annotations and form fields into the content.
How to use Flatten PDF
- 01
Drop in your PDF
Add a document with form fields, annotations, stamps or markup you want to make permanent.
- 02
Everything is baked in
Form fields, comments and annotations are merged into the page content so they become a fixed part of the page.
- 03
Download the flattened PDF
Save a final document where nothing can be edited, unticked, or removed by the next person who opens it.
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About Flatten PDF
Permanently merge all annotations, form fields, stamps and markup into the page content so they can't be edited or removed. Perfect for finalizing filled forms and reviewed documents before sharing.
Make a filled or marked-up document final
Form fields, comments, highlights and stamps are interactive by design: they sit on top of a PDF as separate, editable objects, which is exactly what you want while a document is being filled in or reviewed. But that same flexibility becomes a liability once the document is finished. A filled form can be silently changed or cleared, a set of review comments can be deleted, and different readers may display the markup inconsistently or not at all. Flattening solves this by merging all of those elements into the page content, so what you see becomes a fixed, permanent part of the document.
Once a PDF is flattened, the answers on a form, the annotations on a draft, and any stamps or signatures are painted directly onto the pages. They can no longer be edited, unticked, or removed, and they render the same way in every reader — which is exactly what you want when a document is meant to be a final record.
When flattening is the right last step
Flattening is the natural finishing move for anything that has been filled in or marked up and now needs to be locked. Returning a completed application form, sending out a reviewed contract with its comments made permanent, or archiving a document exactly as it was approved are all cases where you want the content fixed rather than editable. It also sidesteps the common problem of a recipient opening a form in a reader that doesn't show field values correctly, because after flattening there are no live fields left — just the finished page.
It's worth keeping an unflattened copy for yourself if you might need to change the answers later, since flattening is meant to be permanent. Everything runs in your browser with no account and no watermark, so finalising a confidential form or a reviewed agreement keeps the document entirely on your own device, and your original stays intact so you always have an editable version to fall back on.
Questions
Everything runs in your browser. How we keep files private
What does flattening a PDF do?
It merges interactive and overlaid elements — filled form fields, comments, highlights, stamps and other annotations — into the page itself. Afterwards they're part of the fixed content rather than separate objects that a reader could still change or delete.
When should I flatten a document?
When you want to finalise it: a completed form you're returning, a reviewed document you're signing off, or any file where the markup should be permanent and identical for everyone who opens it, regardless of their reader.
Will a filled form still show its answers after flattening?
Yes — that's the point. The values you entered are painted permanently onto the page, so they display the same everywhere and can no longer be cleared or edited in a form-aware reader.
Is my document processed privately?
Yes. Flattening happens entirely in your browser, so your file is never uploaded.