Plugins

Step 1: Log in to your WordPress Dashboard. On the left panel, look for Plugins. 

Step 2: Under the Plugin you wish to remove, you will see the word 'Deactivate'. Click on Deactivate and click Delete. 



Themes

Step 1: Log in to your WordPress Dashboard. On the left panel, look for Appearance > Themes.


Step 2: Navigate to the Theme you wish to remove and click on Theme Details. At the bottom right hand corner there is a Delete button.