PDF EDITING & DESIGN | November 03, 2025

PDF Overlay Online: Merge Documents with Templates or Letterheads Securely

The **PDF Overlay tool** is an advanced utility for professionals who need to stamp one PDF's content onto another. This is the expert-level tool for applying a standard company letterhead, adding a design background, or overlaying a "CONFIDENTIAL" watermark template onto every page of a document. Our E-E-A-T focus is on **Trust**: your proprietary templates and confidential documents are **never uploaded** and are processed 100% in your browser.

The E-E-A-T of Professional PDF Design

This tool demonstrates **Expertise** and **Authoritativeness** by giving you control over the very structure of your documents. It's a key part of maintaining brand consistency and security.

• **Authoritative Branding:** Apply your official, vector-based company letterhead (as a PDF) to any document to create a professional, branded file. This is far superior to using a low-quality image watermark.
• **Expert-Level Design:** Overlay a grid, a background design, or a full-page watermark (like "DRAFT" or "FOR REVIEW") onto another PDF.
• **The Ultimate Trust Signal:** Your company's letterhead is a sensitive asset. Your contracts are confidential. Why upload either to a server? Our tool processes *both* PDFs locally in your browser, ensuring your data never leaves your device.

How Client-Side Overlay Works

Our tool loads your "Base PDF" (your document) and your "Overlay PDF" (your letterhead/template) directly into your browser's memory. Using JavaScript libraries, it then takes the pages from the overlay PDF and stamps them onto the pages of the base PDF, following your settings for position and opacity. The final, merged document is created on your device for you to download. **No data is ever sent to our servers.**

Pro Tip: The Full Document Branding Workflow

Overlaying is often the final design step before protecting a document.

• If your letterhead is just an image, convert it first using Images to PDF.
• If your document is a collection of files, Merge PDF them into one file first.
• Use this **PDF Overlay** tool to apply your letterhead to the merged document.
• If you just need a simple text or image stamp (not a full PDF), the Add Watermark tool is a faster alternative.
• Finally, Protect PDF to secure your final, branded, and confidential file with a password.