Flatten PDF – free online
Lock form answers, comments and stamps into the page so nobody can change them.
How to use Flatten PDF
- Open Flatten PDF on ToolPlanet AI.
- Choose a PDF with forms or annotations from your device, or drag and drop onto the page.
- Flatten form fields and comments into the page.
- Download a PDF that can no longer be edited by mistake.
Frequently asked questions
Is Flatten PDF free?
Yes. Flatten PDF on ToolPlanet AI is completely free, with no sign-up, no watermark and no limit on downloads.
Are my files uploaded when I use Flatten PDF?
No. Flatten PDF runs entirely inside your web browser, so your file never leaves your device and is not uploaded to any server.
What do I need to use Flatten PDF?
Just a web browser such as Chrome, Edge, Safari or Firefox, on a computer or phone. You start with a PDF with forms or annotations and get a PDF that can no longer be edited by mistake.
Do I need to install software or create an account?
No. Everything works online in your browser. There is nothing to install and no account to create.
More Optimize PDF tools
Edit PDF in the same font
Click any text to change it. Prices, names, dates — edits keep the PDF's own font. Add text, boxes and images, then save.
or drop a PDF here · files stay in your browser