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Flatten a PDF, lock in forms and comments
A filled-in PDF form can still be changed, and comments and stamps can be deleted or hidden. Flattening turns them into ordinary page content: they look the same in every reader and can no longer be edited on their own. Do it before you send a signed form or a marked-up document. It all runs in your browser.
or drop files here, or paste with Ctrl/Cmd+V
PDF · up to 50 files · 100 MB each
No file to hand?
Your files stay on your device. Nothing is uploaded. Check it yourself
How to use Flatten PDF
Add your PDFs
Drop one or more PDFs on the box, or click to browse. Up to 50 files of 100 MB each.
Choose what to flatten
Form fields, comments and markup, or both. Links always stay clickable.
Flatten and download
Press Flatten PDF. Each result says how many fields and annotations were flattened.
How flattening works
Every form field and annotation in a PDF comes with an appearance: a small drawing that readers show for it. PlumPDF places that drawing on the page exactly where the reader would, following the rules in the PDF specification, and then removes the field or annotation.
Form fields get their appearances brought up to date first, so what you typed shows even in a form that relied on the reader to draw it. The form itself is then removed from the file.
Text and images already on the page are not touched, and the file is written out without the objects that are no longer used.
Questions about Flatten PDF
What does flattening a PDF do?
It draws form fields and annotations (comments, highlights, stamps, drawings) into the page itself, then removes them as separate objects. What you see stays the same, but the entries can no longer be typed over, unticked or deleted, and every PDF reader shows them identically.
How do I flatten a filled PDF form?
Add the PDF above, keep Form fields ticked and press Flatten PDF. The typed text, ticks and choices become part of the page; the fillable boxes are gone.
Do links still work after flattening?
Yes. Links have nothing to draw, so they are left in place and stay clickable.
Is flattening the same as protecting a PDF?
No. A flattened PDF can still be edited with a full PDF editor; the content is simply no longer a form. To stop others from opening the file, add a password with Protect PDF.
Why do some comments stay after flattening?
A comment that has no picture of its own, such as a sticky note saved by some programs, has nothing to draw, so PlumPDF leaves it as it was. The result says how many were left.
Is it safe to flatten a PDF online?
With PlumPDF the PDF never leaves your device: it is changed in your browser tab, which matters for forms full of personal details.