How to Flatten a PDF (Forms, Comments and Stamps)

To flatten a PDF, open Flatten PDF and add the file. Form fields, highlights, comments' icons, stamps and drawings are merged into the page content straight away, and you download a copy that looks identical but can't be edited — the answers in a form can't be changed and annotations can't be moved or deleted.

How to flatten a PDF

1. Open Flatten PDF.
2. Add the PDF. It's flattened immediately, and the tool tells you how many form fields and annotations it flattened.
3. Click Download flattened PDF.

If the tool says nothing was found, the PDF is already flat — it has no interactive layers to merge.

What flattening means

A PDF can have two kinds of content:

• Page content: the text, images and drawings that make up the page itself.
• Interactive layers on top: form fields that hold your answers, and annotations — highlights, sticky notes, stamps, shapes, ink drawings and placed signatures.

Flattening draws the interactive layers into the page content and removes them as separate objects. The PDF looks the same, but there's nothing left to click, type into or drag.

When to flatten

• Submitting a completed form: stops the answers being changed accidentally — or deliberately — after you've sent it.
• Upload portals that lose your answers: some systems display only page content and show filled-in forms as blank. A flattened form always shows the answers.
• Printing problems: some printers and print shops skip form fields or annotations. Flattened pages print exactly as they look on screen.
• Final versions and archives: a reviewed document with approved stamps and highlights becomes a fixed record.
• Sharing a signed document: flattening merges a placed signature into the page.

What gets flattened

• Text fields, checkboxes, radio buttons and drop-down lists, with their current values.
• Highlights, underlines and strike-throughs.
• Stamps, shapes, ink drawings and signature images.
• Comment icons. The comments' pop-up text is removed, so read and resolve comments before flattening if their text matters.

Links stay clickable, so a table of contents or web links keep working.

How to check a PDF is flat

Open the downloaded file and try to click into a form field or select a highlight. Nothing should respond: the answers are plain text on the page, and the highlight is part of the page's colours. Comment icons no longer open pop-ups.

Flatten as you fill

If you're completing a form, Fill PDF Form has a Flatten option when you download, so filling and flattening is one step. Keep an unflattened copy for yourself in case you need to change an answer later.

Before you flatten

• Keep the original. Flattening can't be undone; you can only return to an editable version from the original file.
• Sign first if you need to, with Sign PDF, then flatten so the signature becomes part of the page.
• Unlock protected PDFs first. A PDF that's password-protected or restricted against editing must be unlocked with Unlock PDF before it can be flattened.

Flattening is not security

A flattened PDF is harder to tamper with casually, but someone with a PDF editor can still change its content, like any PDF. It also doesn't hide anything: text under a highlight remains readable and selectable. To remove information, use Redact PDF.

Frequently asked questions

Will the text still be searchable?

Yes. Form answers become ordinary text on the page, which you can still select and search.

Does flattening make the file bigger?

Usually it stays about the same. Forms with many fields can even get slightly smaller.

Is the PDF uploaded?

No. It's flattened in your browser.