If I can put my letterhead in a Word template, why use an overlay?

If you have the source document and produce it in Word, using a template really is better. Overlay comes into play when you don't have access to the source: PDFs from outside, scanned documents, output produced by other programs, or the need to apply a letterhead to hundreds of existing files in bulk. And when the letterhead changes, overlaying with the new one is much faster than regenerating every document.

Isn't a watermark tool enough for a letterhead?

It's enough for a simple piece of text or a single logo. But real corporate letterheads are usually more complex: a logo at the top, a vertical color band on the side, contact details at the bottom and a thin separator line. Watermark tools take a single element and can't build that layout. An overlay applies a fully designed page, so there's no complexity limit.

An overlay puts the same letterhead on every page, but I want the first page to differ. Is that possible?

Yes. Prepare your overlay file with two pages: the full letterhead on page one and a continuation-page layout on page two. Most tools match overlay pages to the main document in sequence. Alternatively you can split the document into 'first page' and 'the rest,' overlay each separately, and merge — that's more steps but you know the behavior for certain.

Does adding a letterhead make a document official or binding?

No. A letterhead is a visual element and doesn't change the document's legal nature. A document being official has to do with signatures, seals, registration numbers and institutional processes. And because adding a letterhead is easy, seeing one on a document you receive isn't proof it actually came from that organization.

Ways to Add a Letterhead: Overlay, Watermark, or a Word Template?

You need to add your corporate letterhead to a fifty-page proposal. Or you're stamping a logo onto hundreds of archive documents, or adding a confidentiality notice to contracts. There are three different routes, and which one is right depends on where the document came from and how many of them there are.

The three methods in brief

Overlay: applies a PDF page you designed to every page of the target document. There's no limit on design complexity.

A watermark tool: usually takes a piece of text or a single image and applies it with position, rotation and transparency settings. Simple and fast.

A template in the source document: you set the letterhead up as part of the document in Word, Excel, PowerPoint or a design program and produce the PDF that way.

Comparison table

| Criterion | Overlay | Watermark | Source template | |---|---|---|---| | Requires the source file | No | No | Yes | | Design complexity | Unlimited | Low | Unlimited | | Vector logo support | Yes | Usually an image | Yes | | Works on scanned documents | Yes | Yes | No | | Bulk application | Easy | Easy | Every document must be regenerated | | Different layout on the first page | Possible (multi-page overlay) | Hard | Easy (built into Word) | | Does the text flow adapt to the letterhead | No (it can cover text) | No | Yes | | If the letterhead changes | Re-overlay | Reapply | Regenerate every document | | Preparation time | One-time design | None | One-time template |

Scenario 1: You have the source document and produce it in Word

You write your reports in Word and distribute them as PDF.

Winner: the source template. A Word template solves a problem overlay can't: the text flow adapts to the letterhead. When you put the letterhead in Word's header area, the body text automatically starts below it. There's no such adaptation with an overlay — the letterhead you overlay can land on top of the text, and you'll only notice by checking the output.

The Word template's other advantages: a different header on the first page, different layouts for odd and even pages, automatic page numbers and section headings — all built-in features.

You'd prefer overlay here in only one case: if the letterhead changes very often and you already have hundreds of PDFs produced. Then overlaying with the new letterhead is faster than regenerating them all.

Scenario 2: The document came from outside

A subcontractor sent you a PDF and you're going to redistribute it under your own corporate identity. There's no source file.

Winner: overlay. A source template isn't an option. A watermark tool might do for a simple logo, but it can't build a real corporate letterhead — logo, color band, footer, separator line.

The thing to watch in this scenario is the incoming document's margins. If the document is written all the way to the edges, the letterhead you overlay lands on top of the text. In that case you have two options: design a thinner letterhead, or shrink the document slightly first to make room at the top (some tools do this with a "scale to page" option).

Scenario 3: A corporate logo on 300 scanned archive documents

You need to add an institutional stamp to digitized old records.

Winner: overlay. Scanned documents consist of a single large image; there's no concept of a source template.

A watermark tool could do the job too, but one of overlay's advantages becomes obvious here: vector quality. When you overlay a PDF containing your logo as vector, the logo stays sharp when the user zooms in. Watermark tools usually take an image file, and that image is at a fixed resolution; it pixelates when zoomed.

A warning about scanned documents: page sizes can vary from scan to scan. If the scanner settings differed, some pages may be A4 and others a custom size. Because an overlay aligns from the bottom left corner, that causes the logo to appear in different places from page to page. Check the page sizes before doing a bulk job.

Scenario 4: A "DRAFT" stamp on contracts

A temporary marking that will be removed later.

Winner: a watermark tool. This is exactly the job watermark tools were designed for. You type the text, rotate it 45 degrees, set transparency to 20%, apply. Designing a PDF for an overlay would be needless effort.

One warning: neither a watermark nor an overlay is easily removable once applied. Both become part of the content stream. If you're thinking "I'll take it off later," always keep the original.

Scenario 5: A different number on each copy

A report with limited distribution, where each copy carries a mark like "Copy 1/25."

Winner: overlay (repeated). You need to prepare a separate overlay file for each number and overlay them one at a time. 25 copies means 25 operations.

That looks laborious, but there's no alternative: watermark tools also require you to type different text each time, and a source template means regenerating the document 25 times.

If there are a lot of copies (hundreds), setting up automation with command line tools becomes worthwhile.

Scenario 6: Full letterhead on the first page, a small logo on the rest

The classic corporate layout.

Winner: the source template, if possible. Word's "different first page" option handles this in one click.

If there's no source, it can be done with an overlay: you prepare a two-page overlay file (page 1 full letterhead, page 2 small logo) and rely on the tool's page-matching behavior. But be careful here: when the overlay file is shorter than the main document, tools behave differently — some repeat from the beginning (not what you want), some repeat the last page (what you want), and some leave the rest blank.

If you don't know the behavior, the safer route: split the document into "first page" and "remaining pages" with an extraction tool, overlay each with its own letterhead, then merge. Three operations, but a certain result.

Common things to watch

Overlay and watermark are not concealment tools. Both are visual layers; the content beneath stays in the file and can be extracted as text. Removing confidential information requires redaction.

Page size compatibility. Your overlay file should be the same size as the target document. If it isn't, things shift.

Mixed-size documents. If the document contains both portrait and landscape pages, or different paper sizes, a single letterhead won't suit all of them.

Printable area. Letterheads sit close to the page edge and can land in the region printers can't print. If you're planning to print, check the preview.

File size. Use a vector logo; high-resolution PNGs add needless weight. Running compression after the overlay cleans up repeated resources.

Decision summary

If you have the source document and produce it regularly → source template. The text flow adapting to the letterhead is reason enough on its own.
If the document came from outside or was scanned → overlay.
If a simple text stamp is enough → a watermark tool.
If you're applying a complex corporate identity → overlay.
If you're doing bulk work and the letterhead may change → overlay (even if you have the source).

And whichever method you choose: keep the original, check the first and last pages, and look at the preview if you're planning to print.