Can a watermark be added to every slide at once?
Yes. Adding it to the slide master applies it across the deck, rather than repeating the shape on each slide.
Can a watermark be removed again?
If it was added as a shape, yes — find the shape and delete it. That also means a watermark added this way is not a security control; it marks a document, it does not protect it.
Can I use an image rather than text?
Yes. Both text and image watermarks are supported, with control over position, size, rotation and transparency.
Does a watermark survive conversion to PDF?
Yes. It is a shape on the slide, so it renders into the PDF like any other content.
