A lot of Mac users empty the trash by going all the way to the top left corner of the screen with their cursor, (and clicking on Finder -> “Empty Trash…”) However, there is a simpler way of doing this straight from your Dock.
How to empty the trash normally:
All you have to do is right click on the Trash icon in the Dock (press control + left click acts as right click as well) and then click on “Empty Trash.” This will get rid of the files.
You will still be able to recover them using special software.
Here is how to securely empty the trash:
If you want to delete files completely and make sure they are never recoverable, hold command button () and then right click on the Trash icon and then select “Secure Empty Trash” This way sensitive files will be deleted from your Mac securely, and will be beyond recovery.