If you use a File Transfer Protocol (FTP) client to transfer data from your computer to the server of your WordPress host, you can also remove the theme by FTP.
Step 1 : open your FTP client and go to the directory wp-content/themes.
2nd step : in the directory you will find a list of all currently installed themes. Unfortunately, it is not indicated which theme is currently active. Don’t forget to make a backup beforehand. Go to the theme you want to delete and right click. The context menu then opens.
Step 3 : click on ” To delete and confirm that you really want to delete the WordPress theme. The theme is then deleted.
