To change your current theme:
Click Start > Settings > Personalization > Themes.  Under "Change theme", click the tile to switch to the theme you'd like to use.
Note: You can also add a wide variety of new, great looking themes from the Microsoft Store by clicking Get more themes in Microsoft Store, or by downloading featured themes from our website.
To delete a theme:
Click Start > Settings > Personalization > Themes. Right-click (or press and hold) the theme's tile, and select Delete.
Note:Â You cannot delete the currently active theme. Â If you want to delete the currently active theme, first select another theme to use. Â The Settings app will also not allow you to delete default themes.