How to use Flatten PDF
- Select the PDF.
- Choose “Form fields only” or “Everything”.
- Click “Flatten PDF”.
Which mode to choose
Form fields only converts filled fields into regular page content and keeps text selectable. Everything renders each page to an image, which flattens comments, stamps, signatures and layers too — useful when a portal shows annotations incorrectly.
🔒 Your files never leave your device
bopdf processes your documents locally with JavaScript (pdf-lib and Mozilla pdf.js) inside your browser tab. Your PDF is never uploaded, stored or seen by us — you can even disconnect from the internet after the page loads and the tool keeps working. When you close the tab, everything is gone.
Frequently asked questions
Why flatten a form?
Some portals and printers ignore form fields; flattening makes your answers always visible.
Are my files uploaded to a server?
No. Everything happens in your browser on your own device. Files are never sent over the internet, which makes bopdf suitable for confidential documents.
Is there a file size limit?
There is no fixed limit, but very large files (hundreds of MB) depend on your device memory. On phones, files up to about 100 MB usually work well.