Remove a text or picture watermark from a PowerPoint presentation by selecting and deleting it. Alternatively, if you added a background watermark to one or several slides, remove it by resetting those slides' background.
Delete a Text or Picture Watermark
Users can add text or watermark pictures on top of existing slides by editing the Slide Master — the template that defines the layout and overall appearance of the individual slides. Conversely, to delete a text or picture watermark, delete it from your presentation's Slide Master.
Open the View tab and click the Slide Master icon. After clicking the icon, PowerPoint enters Slide Master view, a special mode that lets you edit your Slide Master and the individual layouts your presentation may use.
Click the text or picture watermark to select it and press the Delete key to remove it.
Select Close Master View to save the Slide Master and return to your presentation.
Delete a Background Watermark
Select the slide that contains the background watermark you wish to delete.
Open the View tab and select Format Background.
Click the Reset Background button to remove the background watermark.