How to write a resignation letter that's effective immediately? "A resignation letter should be short and to the point.Simply explain why you're leaving and the date of your departure. Short and sweet is all you need. The letter will end up in your employee file and then forgotten. Learn how to write a short notice resignation letter with this stepbystep guide, template and examples of formal resignation. Please accept my resignation from all duties at the ABC Toilet Brush Company. Aformentioned resignation is in force with immediate effect.