How to Flatten a PDF: 3 Simple Ways for Windows & Mac (2026 Guide)

If you've ever sent a PDF form only to have the recipient accidentally change your data, you need to flatten your PDF. Flattening ensures that your document remains professional, secure, and visually consistent across all devices.

In this guide, we’ll explore the three best methods to flatten PDF files, from using the versatile UPDF editor to quick "Print to PDF" hacks.

Part 1. What Does "Flattening a PDF" Actually Mean?

Flattening a PDF is the process of merging interactive elements—such as form fields, checkboxes, annotations, and digital signatures—into the solid background layer of the document.

• Before Flattening: Elements are "floating" on top. They can be edited, deleted, or moved.
• After Flattening: Elements become part of the static "ink" of the page. They are visible but unchangeable.

This is essential for legal contracts, official invoices, and design proofs where document integrity is a priority.

Part 2. The Best Way to Flatten a PDF (Windows & Mac) - UPDF

While many tools offer a "one-size-fits-all" approach, UPDF gives you granular control. Whether you want to lock just your signature or the entire page layout, UPDF makes it a two-click process.

Why Choose UPDF?

• Selective Flattening: Choose to flatten only forms or only watermarks.
• Cross-Platform: Works seamlessly on Windows, macOS, iOS, and Android.
• Speed: Handles large, multi-page documents in seconds.

Steps to Flatten Your PDF with UPDF:

To flatten your PDF, start by downloading and installing the UPDF app on your device. Here's how to flatten a PDF:

Step 1. Open the UPDF app and click on "Open File" to upload the PDF you want to flatten.

Step 2. Once the document is open, click on "Arrow Down" in the top menu bar.

Step 3. Select "Save as Flatten."

Step 4. A pop-up window will appear, giving you several options: "Flatten Annotation and Forms," "Flatten Watermarks," and "Flatten Cropped Pages."

Step 5. Choose the flattening option that best suits your needs and click "Save As."

Step 6. A new PDF will be created with the selected elements flattened.

By flattening the PDF with UPDF, you ensure that your file remains secure, consistent, and ready for sharing without the risk of edits. Download UPDF today to get started!

Part 3. How to Flatten a PDF via the "Print" Method

If you don't need advanced settings and just want a quick, free solution, the "Print to PDF" method works on almost any device.

To flatten a PDF using the print method, follow these steps:

Step 1. Open the PDF file on your device in any PDF viewer, like UPDF.

Step 2. Click on the "File" button from the top menu bar then click "Print" to open the print dialogue box.

Step 3. In the print window, select "Microsoft Print to PDF" (Windows) or "Save as PDF" (Mac) as your printer.

Step 4. Adjust any necessary print settings, but make sure not to select any interactive options (like printing comments or annotations).

Step 5. Click "Print" and then choose a location to save your newly flattened PDF file.

Part 4. The "Ultra-Secure" Method: Convert to Image-Only PDF

Sometimes, you don't just want to flatten forms—you want to prevent people from even highlighting or copying your text. Converting to an image-only PDF is the ultimate way to "lock" a file.

Using UPDF's OCR (Optical Character Recognition) engine, you can turn a searchable PDF into a flat, non-searchable image file:

Step 1. Download and open the UPDF app and click "Open File" to upload the PDF you want to flatten.

Step 2. Once the file is open, locate the OCR option on the "Tools" and click on it.

Step 3. Select "Text and Pictures Only."

Step 4. Adjust any other settings, such as resolution, based on your preferences or requirements.

Step 5. After making the necessary adjustments, click "Convert."

Step 6. The new image-only PDF file will automatically open.

UPDF offers far more than just the ability to flatten PDFs. With its wide range of features, UPDF allows you to edit, annotate, convert, and manage your PDF files with ease. Whether you're looking to fill forms, add digital signatures, or organize your pages, UPDF has the tools to handle your document tasks efficiently. Its built-in OCR technology, along with translation capabilities, makes it a versatile option for both personal and professional use.

To learn more about how UPDF can streamline your PDF workflow and explore its full range of features, we invite you to watch the video below. The following video provides an in-depth look at the powerful capabilities of UPDF, helping you make the most out of this intuitive PDF tool. By leveraging UPDF's comprehensive features, you can transform the way you work with PDF documents, making tasks faster and more efficient.

Part 5. Frequently Asked Questions (FAQ)

Conclusion

Flattening a PDF is a small step that makes a huge difference in document security. For a quick fix, the "Print" method works fine. But if you need professional control, security, and the ability to selectively flatten layers, UPDF is the most efficient tool on the market.