This template provides more detailed information. How to write a resignation letter that's effective immediately?Please accept this letter as my formal resignation. Today will be my last day of work. In the first sentence, clearly state your intention to resign and that your resignation is effective immediately. Create your immediate resignation letter online in minutes. Customize, download, and resign professionally with ease. Learn how to write a professional resignation letter with our step-by-step guide, easy to use templates and helpful tips. Jim Arkens Resignation Letter.