How to write a resignation letter that's effective immediately? Use one of our resignation letter templates.The complete guide to writing your resignation letter including expert tips, free copyable samples, and templates. Start with a two weeks notice letter. This will serve as a formal, written documentation of your intent to leave and your transition timeline. (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.