Flatten a PDF so it can't be edited
A filled-in form is still a form: the fields stay editable and an annotation can be dragged away by whoever opens it next. Flattening bakes that content into the page. Choose the gentle option, which merges form fields and annotations into the page while keeping the text selectable, or rasterise every page into an image so nothing at all can be changed. Both run in your browser.
How to flatten a PDF
Add the PDF
Drop in the filled form or annotated document you want to lock down.
Choose how far to go
'Bake in fields' keeps the text searchable and merges the interactive layers. 'Rasterise' turns every page into a picture — nothing is editable, but the text stops being selectable.
Save the flattened file
Press Flatten. The result is written locally and downloaded, ready to send.
What Flatten PDF can do
Two strengths
Merge the interactive layers, or rasterise the page completely.
Form fields fixed in place
What you filled in is what the recipient sees, permanently.
Annotations merged
Comments and stamps become part of the page instead of floating over it.
Local processing
Signed forms are flattened on your device, not on someone's server.
Flatten PDF — frequently asked questions
What does flattening a PDF actually do?
It merges the interactive layers — form fields, annotations, stamps — into the static page content. The document looks identical but the pieces can no longer be selected and moved individually.
Does flattening stop someone editing the PDF?
It stops casual editing of fields and annotations. Rasterise mode goes further: the page is an image, so there's nothing left to edit. Neither is access control — for that, add a password with Protect PDF.
Will flattening make the file bigger?
Baking in fields usually makes it slightly smaller. Rasterising often makes it larger, since text becomes pixels — run Compress PDF afterwards if size matters.
Do my PDFs get uploaded to a server?
No. Every tool on Notoo Tools runs as JavaScript and WebAssembly inside your browser tab. There is no server that receives your files — you can disconnect from the network after the page loads and the tool keeps working.
Do I need an account or a subscription?
Neither. There's no sign-up, no email, no free-tier limit and no watermark. Bookmark the tool and it opens straight into the work.