How to Add a Watermark to a PDF for Free

You need to stamp DRAFT across a proposal before sending it for review. Or mark a contract CONFIDENTIAL before sharing it externally. Or add DO NOT COPY to a document you're distributing. In a perfect world, you'd open the PDF in Acrobat, add the watermark, and move on. But Adobe Acrobat Pro costs $20 per month, and you might need to do this once a quarter. Here's how to add a watermark to any PDF for free.

What a PDF watermark actually is

A watermark is text or an image that appears across each page of a PDF, usually at a diagonal, in a semi-transparent style that's visible but doesn't obscure the content underneath. It's embedded in the PDF itself — not added by the viewer — so anyone who opens the file sees it regardless of what software they use.

The most common watermark use cases are: DRAFT (indicating the document isn't final), CONFIDENTIAL (restricting distribution), COPY (distinguishing from the original), SAMPLE (for demo documents), and company names or logos (for branding on reports or proposals).

Watermarks are visual indicators, not security features. They don't prevent someone from copying the document or removing the watermark with the right tools. If you need to actually prevent someone from editing or printing a PDF, you want password protection instead. Watermarks are about communication — making it immediately obvious to anyone who opens the file what its status or handling requirements are.

The free options for adding watermarks

There are several ways to watermark a PDF without paying for Acrobat. Each has tradeoffs.

Option 1: Browser-based tools

The fastest method. You open a website, upload your PDF (or select it locally), type your watermark text, and download the result. This takes under 30 seconds for most documents.

The catch with most online tools is that they upload your PDF to a server to process it. If you're watermarking a document marked CONFIDENTIAL, there's an irony in uploading it to a stranger's server to apply the stamp. Some tools process the file entirely in your browser, which avoids this — the PDF never leaves your device.

Option 2: Microsoft Word

If your original document is a Word file that you haven't converted to PDF yet, Word has a built-in watermark feature. Go to Design → Watermark and choose from the presets or create a custom text watermark. Then export to PDF. This works well but only if you're starting from a Word document — it doesn't help if you already have a PDF.

Option 3: Preview on Mac

macOS Preview doesn't have a dedicated watermark feature, but you can approximate one using the markup tools. Open the PDF, click the Markup toolbar, add a text box, type your watermark text, rotate it diagonally, set the font color to a light gray, and position it in the center of the page. The downside: you have to do this manually for every page. For a 2-page document, it's fine. For a 50-page document, it's tedious.

Option 4: LibreOffice Draw

LibreOffice is free and can open PDFs. You can add text elements, style them as watermarks, and re-export as PDF. Like Preview, this is a manual process — workable for short documents but not practical for longer ones. It also sometimes alters the PDF's formatting during the open/export cycle.

Option 5: Command-line tools

If you're comfortable with the terminal, tools like qpdf or pdftk can add watermarks programmatically. You create a single-page PDF containing your watermark (using any method), then use the tool to stamp it across every page of your target document. This is the most powerful approach for batch processing but requires technical knowledge most people don't have.

What to look for in a watermark tool

Not all watermark tools produce the same result. Here's what separates a good one from a mediocre one:

• The watermark should appear on every page automatically — you shouldn't have to apply it page by page
• The text should be semi-transparent so it's visible without making the underlying content unreadable
• The watermark should be proportional to the page size. A watermark sized for letter paper that's applied to a legal-sized document will look off
• The text should be diagonal (typically 45 degrees) and centered — this is the standard watermark style that people recognize immediately
• The tool shouldn't add its own branding or watermark to your document. Some free tools stamp "Created with [Tool Name]" on your output, which defeats the purpose

Common watermark text and when to use each

• DRAFT — the document is in progress and not yet approved. Use this on proposals, reports, and contracts that are still being reviewed
• CONFIDENTIAL — the document contains sensitive information and shouldn't be shared freely. Common on financial documents, HR materials, and strategic plans
• COPY — this is a duplicate, not the original. Used in legal and compliance contexts where the original carries different weight
• DO NOT DISTRIBUTE — the document is for the recipient only. Stronger than CONFIDENTIAL in implying the recipient shouldn't forward it
• SAMPLE — the document is an example, not the real thing. Common for template demos, product documentation, and training materials
• VOID — the document is no longer valid. Used on cancelled contracts, expired certificates, or superseded policies

Watermarks vs. headers and footers

Sometimes what people actually need isn't a watermark but a header or footer — a small text line at the top or bottom of each page saying something like "Draft — February 2026" or "Company Confidential." Headers and footers are less visually intrusive than a full diagonal watermark and are often more appropriate for internal documents where you want to note the status without making the document hard to read.

If you need a subtle status indicator, a header or footer is usually better. If you need something that's immediately, unmissably visible — something that anyone skimming through the pages can't possibly miss — a diagonal watermark is the right choice.

The quick version

If you need a watermark right now: open a browser-based tool, select your PDF, type your text, download the result. Total time: about 15 seconds. No account, no software, no payment. For a task you might do a handful of times a year, that's all you need.