Use WordArt to mimic a watermark
Click on the worksheet where you want to display the watermark.
On the Insert tab, in the Text group, click WordArt.
WordArt button in Text group
Click the WordArt style that you want to use.
Type the text that you want to use for the watermark.
To change the size of the WordArt, right-click the WordArt. On the shortcut menu, click Font, and then enter a new number in the Size box. Or change it using the anchor points.
To add transparency so that you can see more of the worksheet data underneath the WordArt, right-click the WordArt, and then click Format Text Effects. In the Text Fill category, make sure Solid Fill is selected. If you like, you can select a fill color. Now, drag the Transparency slider to the percentage of transparency that you want.
To rotate the WordArt, select it, and then drag the rotation handle in the direction that you want to rotate the WordArt.