To remove a watermark that you inserted by using the Watermark gallery or dialog box, you can use the Remove Watermark command.
To remove a watermark that you added by inserting a picture in the header and positioning it, you can open the header and delete the picture.
What do you want to do?
Remove a watermark
On the Page Layout tab, in the Page Background group, click Watermark.
Click Remove Watermark.
Remove a watermark that was inserted in the header
Double-click the header area of your document.
The header area is active, the document body dims, and you can scroll down to see your watermark.
Click the watermark to select it.
On the Header and Footer Tools tab, in the Close group, click Close Header and Footer to return to your document.
Note: If your document contains multiple sections that aren’t linked, you need to remove the watermark from each section.