To delete themes in WordPress, you can follow these steps:

1. Log in to your WordPress dashboard.
2. Navigate to “Appearance” and click on “Themes.”
3. On the Themes page, you will see a list of all the installed themes on your WordPress site.
4. Locate the theme you want to delete and hover your mouse over it.
5. Click on the “Theme Details” button that appears below the theme thumbnail.
6. On the theme details screen, you will see a “Delete” button in the lower-right corner.
7. Click on the “Delete” button to remove the theme.
8. A confirmation popup will appear asking if you want to delete the theme. Read the message carefully, as deleting a theme will permanently remove it from your site.
9. Click on “OK” to confirm and delete the theme.
10. WordPress will proceed to delete the theme files from your site, and you will see a success message once the deletion is complete.
11. If you want to delete multiple themes, repeat the above steps for each theme you wish to remove.

It’s important to note that deleting a theme will remove it entirely from your WordPress site, including any customizations or settings associated with that theme. Therefore, make sure to backup your site and double-check before deleting any theme to avoid unintentionally losing any important data or functionality.