# 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.

**URL:** https://convertto.tech/t/flatten-pdf
**Category:** PDF Tools (https://convertto.tech/c/pdf-tools)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

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

## How to use

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

## FAQ

### 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.

## Related tools

- [Fill PDF Forms](https://convertto.tech/t/fill-pdf): Read a PDF's interactive form fields, fill them in, and optionally lock the answers.
- [Create a Fillable PDF Form](https://convertto.tech/t/pdf-form-builder): Place real text fields and checkboxes onto a PDF so other people can fill it in.
- [Edit PDF](https://convertto.tech/t/edit-pdf): Add text, pictures, shapes, arrows, highlights and freehand drawing to any PDF page.
- [Add Page Numbers to PDF](https://convertto.tech/t/add-page-numbers-pdf): Number the pages of a PDF with a custom start, position and format.
- [Compare Two PDFs](https://convertto.tech/t/compare-pdfs): See two versions side by side, overlaid or wiped between — with every changed area outlined.
- [Compress PDF](https://convertto.tech/t/compress-pdf): Reduce PDF file size by re-rendering pages at a lower resolution and quality.
- [Crop PDF](https://convertto.tech/t/crop-pdf): Trim the margins of every page, or just the pages you choose, without re-rendering.
- [Delete PDF Pages](https://convertto.tech/t/delete-pdf-pages): Remove unwanted pages from a PDF and keep everything else intact.