What is Flatten PDF?
Flatten PDF takes the interactive layers of a document – filled form fields, and annotations such as comments, highlights, underlines, drawings, shapes and stamps – and draws them permanently into the page content. The result looks the same in every viewer, prints exactly as shown, and cannot be changed by clicking into a field or deleting a comment. Links are kept clickable. Because the page text and images are not re-rendered, quality stays the same and text remains selectable.
When to use it
- Lock a completed application or tax form so the answers cannot be edited before you submit it.
- Make review comments and highlights a permanent part of a document you are archiving.
- Fix forms whose answers show in one viewer but disappear in another, or vanish when printed.
- Prepare a file for a portal or printer that rejects PDFs with forms or annotations.
Tips for the best result
- Fill the form first with Fill PDF form, then flatten it here, or tick Flatten on download there.
- The summary shows exactly how many fields, comments and markups the PDF contains before you flatten.
- Keep the original file if you may need to edit the form again later; flattening cannot be undone.
Limits and privacy
Annotations are drawn using the appearance stored in the PDF; the rare annotation saved without one is left as it is and reported. Pop-up comment notes are removed, because only their icon is visible on the page. Password-protected PDFs need to be unlocked first. Processing happens entirely in your browser, so your data never leaves your device and there is nothing to sign up for. Files are processed in your browser and never uploaded.
Related tasks
Many people who use Flatten PDF also need Fill PDF form or Sign PDF, and Watermark PDF is one click away. Every MondayKit tool works the same way – open the page, add your input, get the result – with no account, no watermark and no upload.