Lock form fields and notes into the page
You filled in a form online, sent it, and it arrived blank at the other end. Flattening turns the filled-in values into permanent text — it looks right in every reader and nobody can edit it.
A filled PDF form still holds its fields as separate, editable objects. Send it on and the recipient can change your answers, and different PDF readers sometimes show filled fields differently — or not at all, which is why an office occasionally says a form arrived blank.
Flattening merges everything into the page. What you see becomes what the file is: fixed, identical in every reader, and not editable by the next person.
Keep your own editable copy first. Flattening cannot be undone.
No, and that is the point — the values are fixed.
Yes, tick the second option.
No, flattening happens in your browser.
No. Keep the original if you may need to edit it.
Usually slightly smaller, since the field structures are gone.
It stops casual editing and copying, but it is not encryption. Do not treat it as protection for genuinely sensitive material.
🔒 Everything on this page happens inside your browser. Your file is never uploaded to a server.