In this article, we discuss what to include in a professional resignation letter and we share examples of resignation letters you can use for reference. I regretfully have to inform you that, after much thought, I have decided to resign and please accept this letter as a formal notice of my resignation.Learn how to write a professional resignation letter with our step-by-step guide, easy to use templates and helpful tips. You want to give at least a two weeks' notice. In the opening paragraph, clearly state that you are resigning from your position.