The theme is available at no cost to set as background images only on devices running Windows 10.
If the wallpapers rotate too often, after setting up the theme on Settings > Personalization > Background, use the Change picture every drop-down menu to adjust the image rotation frequency. You can find more great themes in the Themes and Wallpapers for Windows 10 section.
To install the National Geographic Underwater theme, use the download link below, click the Get button in the Microsoft Store, click the Apply button, and then select the wallpaper collection from the “Themes” settings page to apply it.
- Painting in Light theme | Download