Edit & compose · guide
What Overlay PDF does
Overlay PDF lays the first page of one PDF over, or under, every page of another: a letterhead, a stamp, a form background or a CONFIDENTIAL banner. Choose how it fits, from actual size to stretched to the page; it is centred on each page. Nothing is flattened into an image, so the text in both stays selectable, and the base document keeps its links and form fields. Both files stay in your browser.
How to overlay two PDFs
- Add the two PDFs Select both PDFs at once: the main document and the PDF to lay over it, such as a letterhead. Open Selected files to check that the main document is listed first. Both open in this browser tab and are not uploaded.
- Choose layer and fit Under Layer, pick Over the document or Under the document; under Fit, pick Actual size, Fit inside page, Cover page or Stretch to page.
- Apply and save Select Apply overlay, check that the overlay does not hide important text, then save the new PDF.
Worked example
Apply a one-page letterhead to a multi-page document.
- Starting point
- Choose the base document first and the letterhead second, preferably with matching paper sizes.
- What to do
- Choose Over or Under the document, then Actual size, Fit inside page, Cover page or Stretch to page. Create and inspect the result.
- Result
- Expect a separate combined copy. Check that the letterhead has not obscured body text or footers.
If the result is not right
If alignment is wrong, check the two page sizes and Fit setting. There is no page matching selector in this view. Use a letterhead source with clear space for the base text.
Limits worth knowing
- An opaque overlay background can hide the base page. Matching paper sizes does not guarantee matching margins.
Questions and answers
How do I add a letterhead to a PDF?
Save the letterhead as a one-page PDF. Select your document and the letterhead together, with your document listed first, and pick Under the document so the letterhead sits behind the text. Its first page is placed on every page of your document.
Can I overlay two PDFs with one of them translucent?
Not with a setting: Overlay PDF has no opacity control and draws the second PDF's page content as it was made, including any transparency it already has. Parts of its page with nothing drawn on them stay see-through, so a stamp or letterhead without a background leaves the document visible around it; a scanned page, or one with a filled background, placed over the document hides everything under it. To make a mark faint, set its transparency in the app you designed it in before exporting. For a line of text such as DRAFT, Watermark PDF draws it at a preset low opacity.
How do I line up two PDFs in an overlay?
Make both the same page size and choose Actual size. The overlay is centred on each page, measured against the part of the page you can see, so pages of the same size line up edge to edge, rotated ones included. There are no offset or position controls, so a small overlay always lands in the middle; if a mark belongs in a corner, put it there on a full-size page before exporting. Only the first page of the second PDF is used, on every page, so pages are not paired one to one. Check the first and last pages, and any page of a different size, before you share the result.
Does an overlay flatten the PDF?
No. The overlay is added as page content, not as a picture of the page, so text in both documents stays selectable and searchable, and the base document's links, annotations and form fields are kept. Layers that the second PDF keeps switched off are drawn as well; the main document keeps its own layers as they were.
Why can't I see the letterhead under my scanned document?
A scanned page is a picture that fills the whole page, and Under the document puts the letterhead beneath it, where the scan's own white paper hides it. For scanned pages, choose Over the document with a letterhead that has no background of its own, so only its logo and lines are drawn on top. The same goes for any document whose pages have a filled background.
My letterhead is A4 and my document is US Letter. Which Fit should I choose?
Fit inside page. It scales the letterhead to about 94% so the whole design fits, keeping its proportions, with a narrow gap at each side. Actual size keeps it full size and centred, which cuts about 9 mm off the top and the bottom of an A4 design on a Letter page. Cover page fills the width and cuts more off the top and bottom, and Stretch to page fills the page exactly but distorts the design.