Hello, adding a watermark to a PDF file can be set. You can do it! Let's see how to add a picture watermark to a PDF file. First of all, we need to prepare Lightning PDF Editor, which is a universal PDF processing tool and provides a simple operation method for editing documents, pictures, links and signatures. Its functions include adding links, watermarks, signatures and so on. Let's see how it watermarks PDF files!

Step 1: Select the browse function in the operation interface and open the PDF file in the pop-up window.

Step 2: Click the page organization function, find the watermark button, click and select Add.

Step 3: Click the new interface to add a pre-prepared watermark image, set the appearance, layout options and page range, and then click OK.

Step 4, click the file, select Save As-Local Folder, and set the storage location.