How to Add a Letterhead, Stamp or Template to a PDF

By the CustomizedPDF Team · How-To · 6 min read

Why this is an overlay job, not a merge

People usually reach for “merge” first, and it does the wrong thing. Merging places files after one another — you end up with a letterhead on page 1 and your document starting on page 2. Overlay places one file on top of another, so the two occupy the same page.

That distinction decides which tool you need:

• Overlay — letterheads, stamps, logos, borders, background templates, “DRAFT” markings. Anything that must share a page with existing content.
• Merge — combining separate documents into one longer file, in sequence.
• Watermark — when you just want repeating text across the page and do not have a designed file to apply.

Putting a letterhead on every page

1. Export your letterhead as a single-page PDF at the same page size as the target document — usually A4 or US Letter. Most design and word-processing tools can “Save as PDF” directly.
2. Open the PDF Overlay tool.
3. Load the document you want branded as the base file, and the letterhead as the overlay.
4. Set Page Alignment to Overlay First Page on All. This is the setting that matters — it repeats your single letterhead page across every page of the base document.
5. Leave Opacity at full for a solid letterhead, or reduce it if the design is dense and would compete with your text.
6. Apply, then download.

If instead you have a multi-page template where page 1 pairs with page 1 and page 2 with page 2, choose Match Pages. For a cover-sheet or first-page-only masthead, choose Single Overlay on First Page Only.

Using a logo or an image instead

The overlay tool accepts PDFs only, so an image needs one extra step. Convert the logo first with Images to PDF or JPG to PDF, then use the resulting file as the overlay.

Two practical notes. Give the logo file the same page dimensions as the target document, otherwise it will not land where you expect — a small square image stretched to A4 is a common surprise. And use a PNG with a transparent background rather than a JPG, since JPG has no transparency and will paint a white box over whatever sits beneath it.

Corner stamps and approval marks

The Overlay Position control offers centre plus the four corners. For an approval stamp, a received-date mark or a small brand device, build it as a PDF sized to the full page with the mark already positioned where you want it, then use Centre. That gives you exact placement, because the position is baked into the overlay file rather than negotiated by the tool.

Use the corner positions when your overlay file is genuinely small — a compact stamp on its own page — and you want the tool to place it.

Making a DRAFT or CONFIDENTIAL marking

Reduce Opacity to somewhere around a quarter to a third and the overlay reads as a background marking rather than content. Combined with Overlay First Page on All, one pass marks an entire document.

Worth being clear about what this does and does not achieve: a DRAFT marking is a visual signal. It does not restrict what anyone can do with the file. If the document genuinely must not be edited or printed, apply real restrictions with Protect PDF. And if the goal is removing sensitive content rather than marking it, an overlay is the wrong instrument entirely — covering text does not delete it. Use Redact PDF, and read how to redact a PDF properly first.

Why the file never leaves your computer

Branded documents tend to be the confidential ones — contracts on company letterhead, signed proposals, client deliverables. The overlay runs entirely in your browser using JavaScript, so neither the base document nor your letterhead is transmitted to a server. Nothing is stored, because nothing arrives. How in-browser processing works covers the mechanics.

Common problems

• The letterhead covers the text. Your overlay has an opaque background. Rebuild it with a transparent background, or drop the opacity.
• It appears on page 1 only. Page Alignment is set to Single Overlay on First Page Only. Switch to Overlay First Page on All.
• Placement is off. The two files have different page sizes. Match them before overlaying.
• The file will not load. It is probably password-protected. Clear the password with Unlock PDF first, where you hold it and have the right to change the file.

Apply your letterhead now

Open the PDF Overlay tool and brand a document in about a minute. For the general mechanics of layering two files, see how to overlay a PDF.

Frequently asked questions