Flatten PDF Files
Make your PDF interactive elements (forms, annotations) permanent and uneditable by flattening them into the document.
About Flatten PDF
Confileo's Flatten PDF tool merges form fields, annotations and layers into a fixed, uneditable PDF. Everything runs in your browser, free and without signup, and your files are deleted automatically after processing.
Filled forms, signatures, stamps and annotations can still be changed after the fact unless the PDF is flattened. Flattening locks the final appearance into the page.
Confileo's Flatten PDF tool merges form fields, layers and markups into a fixed, uneditable document that displays and prints consistently on every reader — ideal for sending a final, tamper-resistant copy. Keep the original if you may need to edit later.
Quick facts
- Price
- Free — no paywall
- Signup
- Not required
- Max file size
- Up to 100 MB per file
- Your files
- Deleted automatically after processing
- Works on
- Any browser — desktop, tablet, mobile
- Watermark
- None on your output
How to use Flatten PDF
- 1Upload the PDF with forms or markups.
- 2The tool flattens every layer into the page.
- 3Download a locked, final PDF.
Why use Confileo
- ✓100% free with no daily limits, watermarks or hidden paywalls.
- ✓No signup or account required — start using it instantly.
- ✓Your files are processed securely and deleted automatically for full privacy.
- ✓Works in any browser on desktop, tablet and mobile — nothing to install.
- ✓Fast processing built to handle real, everyday document workloads.
Flatten PDF — Frequently asked questions
Why flatten a PDF?
Flattening locks the final appearance so forms, stamps and notes cannot be changed or accidentally edited.
Will it still print the same?
Yes. A flattened PDF prints exactly as it appears, with everything baked into the page.
When do I need to flatten a PDF?
When sending a filled form or signed document, to lock its content and prevent fields or comments from being changed afterwards.
Does flattening lock form fields?
Yes. Fillable fields become fixed text that cannot be changed after flattening.
Does flattening fix display issues across devices?
Yes. Merging the layers makes the file display and print consistently across all readers and devices.
Can I edit the file after flattening?
No, and that is the point: a locked, final version. Keep a copy of the original if you need to edit later.
Does flattening merge comments and highlights into the page?
Yes. Annotations, comments and highlights are baked into the page so they always display and print the same way.
Will my signature or stamp stay visible after flattening?
Yes. Signatures, stamps and form entries are merged into the page and can no longer be moved or removed.
Does flattening change the file size?
Usually the size is similar or a little smaller; the content stays the same, it is just locked in place.
Is this tool really free?
Yes. Every Confileo tool is free to use with no daily caps, no watermark on your output and no credit card required.
Do I need to create an account?
No. You can use the tool straight away without signing up or logging in.
Are my files safe and private?
Yes. Your files are processed for the task you requested and then deleted automatically — they are never shared or kept.
Does it work on my phone?
Yes. The tool runs in any modern browser, so it works the same on desktop, tablet and mobile with nothing to install.