About the PDF Overlay
Tezmy's PDF Overlay tool places the pages of one PDF on top of, or behind, the pages of another. It's the quick way to put your company letterhead on a letter exported without it, add a stamp or a “Copy” mark, or give every page a background design. Use the overlay's first page on every page, or match the pages one to one. The overlay stays sharp because it's added as the original PDF content, not a picture, and everything happens in your browser, so neither file is uploaded.
Updated October 2026
How to use the PDF Overlay
- 1Click Select PDF file and pick your document.
- 2Add the overlay PDF: your letterhead, stamp or background.
- 3Choose On top or Behind, which pages to change, and the size.
- 4Lower the opacity if the overlay should look faint.
- 5Click Add overlay, check the preview and download your PDF.
What people use PDF overlay for
- Adding a company letterhead to letters, quotes and invoices exported from another program.
- Stamping “Paid”, “Copy” or “Approved” onto documents, using a stamp saved as a PDF.
- Putting a background design or border behind certificates, menus or flyers.
- Filling a pre-printed form: overlay your typed answers on the blank form, page by page.
- Adding the same footer, logo or legal text to every page of a report.
Choosing the options
On top or Behind decides the layer. A stamp or logo usually goes On top. A letterhead or full-page background usually goes Behind, so your text is printed over it just like on pre-printed paper.
First page on all uses only the first page of the overlay PDF, on every page you choose. Page by page lines the two documents up page for page. Apply to lets you change all pages, only the first page (common for letterheads), or pages you type, such as 1, 3-5.
Size matters when the two PDFs have different page sizes, for example an A4 letterhead on a US Letter document. Fit page is the safe choice. Opacity lowers how strongly the overlay shows, which is handy for backgrounds and watermarks.
Tips for a clean result
- Make the overlay PDF the same page size as your document, and leave the rest of its page empty (not white-filled) so it doesn't hide anything.
- If your letterhead disappears when set Behind, the document's pages are probably solid images (scans). Use On top instead.
- Check the preview after adding the overlay; if text and design overlap, adjust the design or try the other layer.
- Pages with their own rotation are handled, so the overlay appears upright on every page.
Overlay, merge or watermark?
Merge PDF puts documents one after the other, adding pages. Overlay keeps the same number of pages and layers the content of one PDF onto the other. Watermark PDF adds a line of text such as “Confidential” without needing a second file. Pick overlay when you already have a design as a PDF.
On a phone or computer, and private
PDF Overlay works in any modern browser on Windows, Mac, iPhone, Android and Chromebook, with nothing to install. Both PDFs are read and combined on your device and never uploaded, which keeps letters, invoices and certificates private. To put your own signature on top of a page, use Sign PDF, and add page numbers afterwards with Add Page Numbers to PDF.
Features
- Put the overlay on top or behind
- First overlay page on every page, or page by page
- All pages, first page only or chosen pages
- Fit, stretch or original size
- Adjustable opacity and a preview
- Private: files never leave your device
Frequently asked questions
How do I add my letterhead to a PDF?
Save your letterhead as a PDF (for example from Word: File > Save as PDF, with only the header and footer on the page). Open your letter here, add the letterhead as the overlay, choose Behind if the letterhead has a coloured area, or On top otherwise, and click Add overlay.
What's the difference between On top and Behind?
On top draws the overlay over your page, like a stamp; it can cover text if they overlap. Behind puts it underneath, like printing on pre-printed paper; your text stays on top. Behind only shows through where the page is see-through, so it doesn't work with scanned pages, which are solid pictures.
Can I put the letterhead on the first page only?
Yes. Under Apply to, choose First page. You can also choose Choose and type pages, such as 1, 3-5.
What does Page by page do?
When the overlay PDF has several pages, Page by page puts overlay page 1 on page 1, overlay page 2 on page 2 and so on. That's useful for numbered forms or a different design on the first and the following pages. If the overlay has fewer pages, the rest of your document stays as it is.
What if the two PDFs are different sizes?
Fit page scales the overlay to fit inside each page without distorting it and centres it. Stretch makes it cover the whole page, even if it gets distorted. Original keeps its real size, centred.
Will the overlay be blurry?
No. The overlay page is added as PDF content, not turned into an image, so text and lines in it stay sharp at any zoom. Links inside the overlay PDF aren't carried over, though.
Can I make a faint background or watermark?
Yes. Lower the Opacity slider, for example to 20–30%, for a faint design. For a simple text watermark there's also our Watermark PDF tool.
Are my files uploaded?
No. Both PDFs are combined in your browser, so nothing is sent to a server.