Flatten PDF — Lock Your Filled Form
Turn a fillable form into a flat document so the answers cannot be edited after you send it.
Quick answer: Flatten a fillable PDF free: form fields and annotations become fixed page content, so nobody can change the answers. Runs in your browser — the file is never uploaded.
How to use
- Load the filled form.
- Flatten it.
- Download the flat PDF.
About this tool
A filled form is still editable: anyone who opens it can click a field and retype the answer, which matters when the document is an invoice, a consent form or an application. Flattening merges the field values into the page content, so the document behaves like a printout. This is also the fix when a form will not submit through a government or bank portal that rejects interactive fields. Everything happens locally. Your file never leaves this page — pdf-lib runs in your browser, there is no upload endpoint on this site, and the document is dropped from memory when you close the tab.
FAQ
Is my form uploaded?
Will the answers stay visible?
Can I un-flatten it later?
Does it keep the text selectable?
Why would a portal reject an interactive PDF?
Any page limit?
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