Microsoft Excel doesn’t come with a built-in watermark button. But you can use an image, like a logo, to create a watermark. Create a watermark. Select Insert > Header & Footer. Tap on the header and on the Header & Footer Elements tab on the ribbon, click Picture. Select one of the available options to insert your image. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.