How do you delete an application from an iMac?

Move it to the trash

Which program are you asking about. Some apps do not delete via the trash, though as Axeman suggests, it's your first choice.

Incidentally, it is wise never to install an app or program that you haven't got uninstall details for.

Move it to the trash the applications and end

Additionally, you should not remove any apps installed by the system.

Any third party apps installed with an installer should be uninstalled by using their uninstaller app.

Any you simply installed by dragging them into your Applications folder can be moved to the trash.