To deactivate a WordPress theme, follow these steps:
1. Login to your WordPress website as an administrator.
2. Click on the Appearance option from the sidebar menu.
3. In the Appearance section, click on Themes.
4. You will see a list of active themes. Hover over the theme you want to deactivate and click on the Theme Details button.
5. On the Theme Details screen, you will see an option to Deactivate the theme on the bottom right corner.
6. Click on the Deactivate button.
7. The theme will now be deactivated and you will see the message “Theme deactivated.“
8. You can activate a different theme or keep it deactivated if you want.