Flatten PDF

Flattening a PDF merges all interactive elements — fillable form fields, annotations, comments, checkboxes, radio buttons, and digital signatures — into the static page content. Once flattened, these elements become permanent, non-editable visual parts of the document that cannot be modified or removed. This is the standard way to finalize filled forms before submission to prevent accidental changes. PDFly flattens your PDF entirely in your browser.

Upload your PDF with form fields or annotations, and the tool converts everything into flat, non-editable page content. The resulting PDF looks visually identical to the original, but all interactive elements are now baked into the page as static graphics and text. You can verify the flattening worked by trying to click on former form fields — they should be completely unselectable and uneditable.

Flattening is essential before sharing filled forms to prevent recipients from accidentally or intentionally modifying your responses after submission. It's also a good security practice — flattened PDFs don't carry form field metadata that could expose previous entries or hidden data. Flattening also typically reduces file size somewhat by removing form field structure and metadata. For protecting a flattened document further, use the PDF Protect tool to add a password. Always keep a copy of the original unflattened form as a backup in case you need to make changes later.