Remove themes you no longer use to keep your WordPress installation tidy. You cannot delete the active theme; switch to another theme first if needed.
Log in to your WordPress admin dashboard.
Go to Appearance > Themes.
Select an inactive theme you want to remove. Hover over it and click Theme Details.
In the theme details window, click Delete, usually at the bottom-right.
Confirm the deletion when prompted.
The theme is now removed from your WordPress site.