4 Simple Ways to Make a PDF Non-Editable with UPDF

You just finished the "final" version of a contract, a signed form, or a report, and now you're one accidental edit away from someone quietly changing a number, a clause, or a signature field before it lands in the wrong inbox. UPDF gives you four different ways to lock that down, and which one you need depends on what you're actually worried about — casual edits, unauthorized copying, or a form field someone shouldn't be able to touch. Download UPDF for free below, then follow along with whichever method matches your situation, on Windows, Mac, or mobile.

Part 1. Which Method Do You Need? (Quick Routing Table)

Part 2. Method 1: Print a PDF as an Image (Windows)

UPDF's Windows app can "print" your PDF into a new file, flattening the text and images into a single picture per page. Anyone who opens it afterward can view the page but can't select or edit the underlying content.

Print a Single PDF as an Image

Step 1. Open the PDF in UPDF and click the dropdown arrow next to Save, or press Ctrl+P.

Step 2. In the Print window, choose Microsoft Print to PDF as the printer and check Print as Image.

Step 3. Set the paper size, orientation, and page range, then click Print and choose where to save the file.

Batch (multiple PDFs at once)

Step 1. From the UPDF homepage, click Tools > Print.

Step 2. Click Add Files to import every PDF you want to convert.

Step 3. Choose Microsoft Print to PDF, check Print as Image, and click Apply. To combine several pages onto a single image, switch to the Multiple tab first and set your layout.

Part 3. Method 2: Add a Permissions Password (Desktop & Mobile)

A permissions password lets people open and read your PDF but blocks editing, copying, or printing unless they know the password. It's the right call when you want to control who can change the file, not just make it visually static.

Add a Permissions Password to A Single PDF (Windows & Mac)

Step 1. Open the PDF, click the dropdown arrow next to Save, and choose Protect Using Password.

Step 2. Click Add under Permissions Password.

Step 3. Enter your password in both fields, then set Printing and Changes to Not Allowed.

Step 4. Click Save and choose where to store the protected file.

On UPDF Mobile (iOS & Android):

The mobile app currently locks the whole file rather than setting the same open-to-view-but-not-edit permissions as desktop:

Step 1. Open the PDF in UPDF for iOS or Android.

Step 2. Tap the three-dot icon and select Password.

Step 3. Enter your password and tap Confirm, then save the protected file.

Add a Permissions Password to Batch PDFs (Windows & Mac)

Step 1. From the homepage, go to Tools > Encrypt.

Step 2. Click Add Files to import the PDFs, then click Add under Permissions Password and set your restrictions once.

Step 3. UPDF applies the same password and restrictions to every file in the batch.

Mac-only alternative — the system Print dialog:

If you'd rather not open UPDF's protection panel, macOS itself can add a permissions password when printing:

Step 1. Open the PDF and press Command+P.

Step 2. Click the PDF button at the bottom of the print window and choose Security Options.

Step 3. Check the options to require a password for opening or for printing and copying, enter your password in both fields, then save the protected copy.

Alternate Mac Method For Batch PDFs

Step 1. First, in the “Tools” section, click the “Print” option under the Batch PDFs category.

Step 2. After that, you need to import your PDFs by clicking the “Add Files” option. Then, press the “Print” option to access the printing interface.

Step 3. Now, follow the same process that we did for a single PDF and save a copy of the protected PDF. This way, no one can edit or print your set of PDFs without the permissions password.

Part 4. Method 3: Flatten the PDF (Windows & Mac)

Flattening merges form fields, annotations, and stamps into the page itself, so they stay visible but stop being interactive. It's built for documents where the content of a form or comment matters, not just the plain text.

Step 1. Open the fillable or annotated PDF, click the dropdown arrow next to Save, and choose Save as Flatten.

Step 2. In the Flatten Settings window, pick which elements to lock — Forms, Watermarks, Comments, or Cropped Pages. Select all of them if you want everything frozen at once.

Step 3. Click Save As, choose a location, and click Save.

Part 5. Method 4: Export the PDF as Images (Desktop & Mobile)

This is the most complete lock: the PDF becomes a set of image files, so there's no text layer left to select, copy, or edit — with or without a password.

Desktop:

Step 1. Open the PDF, click Tools, and choose Image under the PDF Converter section.

Step 2. Pick your output format, set the page range, and choose whether to combine pages into one image or export each page separately.

Step 3. Click Convert and choose where to save the image files.

Mobile (iOS & Android):

Step 1. In UPDF Mobile, tap Tools, then tap PDF to Image in the converter section.

Step 2. Import the PDF from your phone or cloud storage, then choose the image format and save location.

Step 3. Tap Continue — the image version saves to your device.

Part 6. Password vs. Flatten vs. Image-Only: What's Actually Different?

These three non-editable methods sound similar but lock a PDF in very different ways:

• A permissions password is a locked drawer. The contents inside are completely normal PDF text and objects — you just need the key (the password) to open the drawer for editing, copying, or printing.
• Flattening is laminating a printed page. The content shows through exactly as it did before, and you can hand it to anyone without a key, but nothing on the page can be peeled up and rearranged anymore.
• Exporting as an image is photographing the page. The "text" isn't text at all anymore — it's a picture of text, so there's nothing left to select or extract in the first place.

Part 7. Method Comparison

Part 8. If Something Still Goes Wrong (Edge Cases)

• "I flattened my form, but when I reopened it in a different PDF reader, the fields looked editable again." Some viewers render flattened content inconsistently. Check the flattened file in the actual app your recipient will use — like Adobe Reader — not just inside UPDF, before you send it.
• "I added a permissions password, but the recipient just screenshotted it and ran OCR to get the text out." A permissions password blocks copy/paste and editing inside a compliant reader, but it can't stop a screenshot-and-OCR workaround. If that's the real risk, an image-only export doesn't remove that risk either — no method fully prevents someone from re-typing what they can see — but flattening or printing as image at least means there's no text layer to lift directly.
• "I need this PDF non-editable now, but I might have to update it myself in six months." If you used a permissions password, you can remove it later with the same password and edit normally. Flattening and image export are different — both destroy the original editable layer for good, even for you, so keep your original file somewhere safe if you chose either of those two methods.
• "My flattened PDFs came out noticeably larger than the originals." Flattening embeds rendered comments, stamps, and form fields as fixed content instead of lightweight interactive objects, which can add file size. Compress the file afterward if size matters for emailing.

Part 9. FAQ

Conclusion

Four methods, four different jobs: Print as Image for a free, Windows-only lock; a permissions password when you want to control who can edit or copy; flattening when forms, comments, or stamps need to stay exactly where you put them; and exporting as images when you want the strongest lock available, on desktop or mobile. Match the method to what you're actually protecting against, and your "final" PDF stays final — on Windows, Mac, iOS, and Android.