How to write a resignation letter that's effective immediately? Learn how to write an immediate resignation letter with our comprehensive guide, including tips, examples, and a customizable template.Start with the facts and be direct. This guide will provide you with helpful tips and advice on how to write a clear and concise resignation letter. Start with a two weeks notice letter. This will serve as a formal, written documentation of your intent to leave and your transition timeline. I am writing to formally inform you of my decision to resign from my position at Wilson Co. as Sales Manager. (For example, "I regret to inform you that I will be resigning from my position, effective immediately. Please accept this letter as my formal resignation. Today will be my last day of work.