Edit
Flatten PDF
Lock form fields and annotations into the page.
Processed locally — your files never leave your device
How to use Flatten PDF
- 1
Open your PDF.
- 2
Choose what to flatten: form fields, annotations, or both.
- 3
Click Flatten.
- 4
Download the locked-in document.
About this tool
Flattening converts a PDF's interactive layer — form fields, comments, highlights — into ordinary page content. The text stays visible, but it stops being editable. It's the difference between sending someone a form they can quietly change and sending them a document that says what it says.
The most common reason to flatten is submitting a completed form: flattened answers can't be altered after the fact, and they render identically in every viewer — including the ones that display unfilled fields as blank. The second reason is print-prep and archiving, where interactive elements are noise.
Two independent switches give you control: flatten form fields (values become page text), and strip annotations (comments, highlights and markup are removed). Use both for a fully static document, or just one — for instance, locking form answers while keeping review comments visible.
Frequently asked questions
Can flattening be undone?
No — that's the point. Once flattened, fields and annotations are ordinary page content. Keep your original file if you might need the interactive version again.
Why do my form answers disappear in some viewers without flattening?
Some viewers don't render field values reliably, especially in print. Flattening bakes the values into the page so every viewer and printer shows them.
What exactly happens to annotations?
With "remove annotations" on, comments, highlights and similar markup are stripped from every page. Form fields are handled separately by the flatten-forms switch.
Does flattening reduce file size?
Often slightly, since interactive structures are removed. The visible content is unchanged, so don't expect compression-level savings — that's what the Compress PDF tool is for.