Use Flatten PDF - free
Frequently asked questions
Can I unflatten a PDF after saving?
No. Flattening is irreversible. The fields are merged into the page image. Always keep a copy of the original filled-form PDF if you may need to edit values later.
Why would I flatten instead of just saving?
Flattening prevents recipients from changing form values, removes annotation layers that some viewers show as pop-ups, and ensures the document looks identical in all PDF viewers.
Does flattening reduce file size?
Often yes - removing interactive field structures and annotation data can noticeably reduce file size, especially for forms with many fields.