Stack one PDF over another — add a letterhead, watermark sheet or background.
Overlay one PDF on top of (or behind) another, page by page. Use it to apply a letterhead, a stamp sheet, a watermark layer or a background design to an existing document. Files are processed securely and never stored.
Upload your file using the tool above.
Adjust any settings to your preference.
Click the process button and wait for results.
Download your output using the download button.
Applying a letterhead or branded background to plain documents is the classic case — generate invoices without styling, then overlay the company template so every page carries the design. It is also used for stamps, borders, and pre-printed form backgrounds that data is laid over.
The overlay is drawn over the base document, so anything opaque in it will hide what sits underneath. For letterheads and backgrounds this is why transparency matters: a template with a solid white page will obscure your content entirely rather than framing it.
A single-page overlay is typically repeated across every page of the base, which is what you want for a letterhead. Where both have multiple pages, they are paired in order — so check the result if the counts differ, since the pairing may not be what you assumed.
Yes, Overlay PDFs is completely free. No signup, no account, and no watermark on outputs. A Pro tier is available for 100 AI ops/day and larger file sizes.
Overlay PDFs uploads your file over an encrypted connection to our own processing server, converts it, and returns the result. The file is deleted immediately after processing and is never used for anything else. It is not sent to any third party, and we keep no copies.
Drop the base PDF
Stack a letterhead, stamp or background onto it
Drop your file into the stage to begin.
What overlaying does: It stacks one PDF on top of another, page by page — so you can drop a letterhead, watermark sheet, stamp, or background design onto an existing document.
Target specific pages: Apply the overlay to every page, or only the ones you list (e.g. 1, 3, 5-7). Pages you don’t select are left exactly as they were. A multi-page overlay is placed in order across your selected pages, repeating if there are more pages than overlay sheets.
Above vs behind: Place the overlay on top of the content (for stamps and marks) or behind it (for backgrounds and letterheads that shouldn’t cover the text).
Privacy: Both PDFs are sent over an encrypted connection, merged in memory, and deleted immediately after — never stored.