If the background is an image, you can extract and retouch it in Photoshop, then place the image and the original PDF in Indesign and export to a PDF with bleed Select Bleed and Slug; Enter” for top, bottom, left, and right values; Check the Preview box in the dialogue box to see what the bleed area will look like on your document (it will be represented by a red guide). Computer. Any elements that bleed must extend to the red box. The software analyzes the print file along the PDF trim box or a