Flatten PDF

Flattening a PDF converts its interactive elements — form fields, signatures, sticky notes, and other annotations — into static content that is permanently part of the page. Once flattened, nobody can edit the form values, move the annotations, or modify what was captured. That is exactly what you want before sending out a signed contract, archiving a filled-in tax form, or publishing a finalised document to the public.

Without flattening, a PDF with form fields is technically still a live form: any recipient with a PDF reader could overwrite the values, change the checkbox states, or delete the signature you just added. For legal, compliance, and record-keeping purposes this is unacceptable. Flattening eliminates that risk by merging everything into the underlying page drawing, producing a file that looks identical but cannot be modified in the normal way.

PDF Genie's Flatten PDF tool runs entirely in your browser using the PDF-lib library. Your document is loaded into memory, its form is flattened, and the result is downloaded directly to your device — the file never travels to our servers. That keeps sensitive signed documents and filled forms private throughout the process.

This tool is used daily by HR departments archiving signed onboarding forms, legal teams finalising contracts and engagement letters, accountants filing completed tax returns, and small businesses sending signed proposals to clients. It is also the natural companion to our Sign PDF tool: add your signature with Sign PDF, then run the result through Flatten PDF to make sure it can never be removed or moved.