How to Add a Watermark to a PDF (Free, Step-by-Step Guide)

A few months ago, a contractor I was working with sent me a draft proposal and asked me to review it. Across every single page, in big diagonal gray letters, it said "DRAFT." I thought it looked a bit over the top at first. But then I realized something: without that watermark, the draft version could easily get confused with the final version. Someone could forward it. Someone could print it and hand it to a client. The watermark was doing exactly what it was supposed to — making absolutely clear that this document was not final.

Watermarks are one of those simple tools that solve real problems. They mark documents as confidential, flag drafts, show ownership, and discourage unauthorized sharing. And adding one to a PDF is way easier than most people think.

When You Actually Need a Watermark

Not every PDF needs a watermark. Let's be honest — slapping "CONFIDENTIAL" on your grocery list is a bit much. But there are genuine use cases:

• Draft documents. You're sharing a proposal, report, or contract that isn't finalized yet. A "DRAFT" watermark prevents anyone from treating it as the final version.
• Confidential information. Employee records, financial statements, legal documents. The watermark doesn't prevent someone from sharing the file, but it does make clear that they shouldn't.
• Copyright protection. Photographers, designers, and writers sometimes watermark preview versions of their work. It lets the client see what they're getting without giving away the full-quality version for free.
• Branding. Some companies put their logo as a subtle watermark on all outgoing documents. It's not about security — it's about brand consistency.
• Review copies. Manuscripts, proofs, and pre-release materials often carry watermarks to track distribution. Some publishers even put the reviewer's name as the watermark, so if the document leaks, they know who shared it.

If any of those apply to you, read on.

Text Watermarks vs. Image Watermarks

There are basically two types of watermarks you can add to a PDF:

Text watermarks are words or phrases stamped across the page. "DRAFT," "CONFIDENTIAL," "SAMPLE," "DO NOT DISTRIBUTE" — that kind of thing. They're usually displayed diagonally in a semi-transparent font. Text watermarks are the most common type and they're the easiest to create.

Image watermarks are logos or graphics placed on the page. A company logo in the corner, a photographer's signature across the center of an image. These require a bit more setup because you need the image file, and you need to position and size it carefully so it doesn't overwhelm the actual content.

Most people need text watermarks. Image watermarks are more of a branding/copyright thing.

Method 1: PeacefulPDF (Free, Private, Browser-Based)

I'm going to start with this one because it's what I use. PeacefulPDF's watermark tool lets you add text watermarks to any PDF directly in your browser. Nothing gets uploaded anywhere — everything is processed locally on your device.

How to use it:

1. Open the Watermark tool
2. Upload your PDF (remember, it stays on your computer)
3. Type your watermark text
4. Adjust the position, angle, opacity, font size, and color
5. Preview and download

The opacity control is really important. You want the watermark visible enough to be read, but not so dark that it makes the actual content hard to read. I usually go with something around 20-30% opacity for a diagonal "DRAFT" or "CONFIDENTIAL" watermark. For a small copyright notice in the corner, you can go a bit darker — maybe 40-50%.

A quick tip: if your document has both light and dark sections (like pages with images), test the watermark on several pages before committing. A light gray watermark that's perfectly visible on a white page might disappear completely over a dark photo.

Method 2: Adobe Acrobat Pro

Acrobat's watermark feature is under Edit PDF → Watermark → Add Watermark. It supports both text and image watermarks with fine-grained control over position, rotation, opacity, and page range.

One feature Acrobat has that most free tools don't: you can choose to place the watermark behind the content (so text sits on top of it) or in front of the content (so the watermark overlays everything). Behind is better for readability; in front is better for security.

You can also specify which pages get the watermark. Maybe you only want it on the first page, or only on even pages, or on pages 3 through 15. Acrobat handles all of that.

The obvious downside: $20/month. If watermarking PDFs is something you do daily, maybe it's worth it. If it's a once-in-a-while thing, you're paying a lot for a feature you rarely use.

Method 3: LibreOffice (Free, Desktop)

LibreOffice can open PDFs (sort of). When you open a PDF in LibreOffice Draw, it converts the document into an editable format. You can then add text boxes or images as watermarks, position them however you want, and export back to PDF.

The problem? LibreOffice's PDF import isn't perfect. Complex layouts, unusual fonts, and embedded images sometimes get mangled. For simple, text-heavy documents, it works fine. For anything with complex formatting, you might end up spending more time fixing the layout than adding the watermark.

I've used this method exactly once. It worked, but the experience was frustrating enough that I haven't gone back. Your tolerance for fiddly software may vary.

Method 4: Python Script (For Developers)

If you're comfortable with Python, the PyPDF2 or reportlab libraries make watermarking straightforward. The basic approach:

1. Create a single-page PDF containing just the watermark text (using reportlab)
2. Merge that watermark page onto every page of your original document (using PyPDF2)

It's maybe 30 lines of code. The advantage is you can script it — if you need to watermark 200 documents with different text, a script beats doing it manually one by one. I've set up automated watermarking pipelines for companies that generate a lot of draft documents. Works great once it's running.

Obviously this isn't for everyone. If the phrase "Python script" makes you break out in hives, stick with a GUI tool.

Watermark Best Practices

Keep It Readable But Not Overwhelming

The worst watermarks are the ones that make the document unreadable. I've received PDFs where the "CONFIDENTIAL" stamp is so dark and large that I can barely read the actual text underneath. That defeats the purpose — you want people to actually be able to read the document.

Go with a light gray color (not red, not black) at 20-30% opacity. Diagonal placement across the center of the page is standard. The text should be large enough to notice but not so large that it dominates the page. I typically use a font size between 48 and 72 points for full-page diagonal watermarks.

Be Specific With Your Text

"DRAFT" is fine. "CONFIDENTIAL" is fine. But sometimes more specific text is better. "DRAFT - Not for Distribution - v2.3" tells the reader exactly what they're looking at. "Review Copy for [Name]" helps track who has the document.

For legal or compliance reasons, some organizations require specific watermark text. Check with your legal team before choosing your wording — they might have opinions.

Don't Rely on Watermarks for Security

This is important. A watermark is a label, not a lock. Anyone with basic PDF editing skills can remove a watermark. It's a deterrent and a visual indicator, not a security measure.

If you need actual security, combine watermarks with other measures: password protection, restricted permissions, or DRM (digital rights management). A watermark says "please don't share this." Encryption says "you can't open this without the password." They serve different purposes.

Test Before Sending

Always open the watermarked PDF and scroll through it before sending it out. Check that the watermark is visible on every page, that it doesn't overlap with important content in an unreadable way, and that it looks professional.

I once sent a watermarked document where the watermark was perfect on pages 1-10 but completely invisible on pages 11-20 because those pages had a colored background. Embarrassing. A quick scroll-through would have caught that.

Removing Watermarks

What if you received a watermarked document and need to remove the watermark? Maybe the draft was approved and now you need a clean version.

If you added the watermark yourself using a tool that keeps it as a separate layer (like Acrobat), you can usually remove it through the same tool. In Acrobat, go to Edit PDF → Watermark → Remove.

If someone else added the watermark and you don't have the original, it gets trickier. Watermarks that are "flattened" into the PDF (merged with the content layer) are much harder to remove. You can try editing the PDF to cover or delete the watermark elements, but results vary.

The honest answer: if you need a clean version, ask the person who sent you the watermarked one. They probably have the original.

Wrapping Up

Adding a watermark to a PDF is one of those tasks that sounds more complicated than it is. For a basic text watermark — which is what most people need — it takes less than a minute with any decent tool.

My recommendation for most people: use a browser-based tool that processes files locally. It's free, private, and fast. If you need image watermarks or page-specific placement, step up to Acrobat or a scripting approach.

Just remember: watermarks communicate intent. They tell the reader "this is a draft" or "this is confidential." They're a social tool, not a technical security measure. Use them for what they're good at, and use encryption for the rest.