Skip to content
Convertto

Flatten a PDF — Lock Form Fields and Annotations

Turn fillable form fields into fixed page content so nobody can edit the answers.

Flattening a PDF converts fillable form fields into ordinary page content, so the values become part of the page and cannot be changed by a reader. It is what you do before sending a completed application or contract. Flattening does not encrypt or protect the text itself — that is a different thing entirely.

Runs in your browser
Privacy
Runs entirely in your browser — nothing is uploaded
Cost
Free, unlimited, no sign-up

Frequently asked questions

Does flattening make a PDF uneditable?

It makes the form fields uneditable. It does not make the document uneditable — anyone with a PDF editor can still alter flattened content, and the text remains selectable and extractable. If the goal is proof the document has not changed, that needs a digital signature, not flattening.

Why did my form values disappear after flattening in another tool?

A field whose appearance stream was never generated has nothing to bake in, so a naive flatten produces an empty box. This regenerates appearances before flattening when the first attempt fails, which covers the usual cause.

How to use the flatten pdf forms

  1. 1Select your pdf file — the file stays on your device and is never uploaded.
  2. 2Turn "Keep the current field values visible" on or off as needed.
  3. 3Press Run, then download the result when it is ready.

Embed this tool

Put the working flatten pdf forms on your own site. It runs in your visitors' browsers exactly as it does here — free, no account, nothing uploaded.

Share this tool

Related tools

Fill PDF FormsRead a PDF's interactive form fields, fill them in, and optionally lock the answers.Create a Fillable PDF FormPlace real text fields and checkboxes onto a PDF so other people can fill it in.Edit PDFAdd text, pictures, shapes, arrows, highlights and freehand drawing to any PDF page.Add Page Numbers to PDFNumber the pages of a PDF with a custom start, position and format.Compare Two PDFsSee two versions side by side, overlaid or wiped between — with every changed area outlined.Compress PDFReduce PDF file size by re-rendering pages at a lower resolution and quality.

Last updated

More pdf tools