Learn how to write a short notice resignation letter with this stepbystep guide, template and examples of formal resignation. How Long Should Your 1-Month Notice Resignation Letter Be?Up to 150 words is good enough. In this article, we discuss how to create a 30day resignation letter, why it's important and provide a template and examples to help you write your own. 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. Start with a two weeks notice letter. This will serve as a formal, written documentation of your intent to leave and your transition timeline. But how do you transition from a fulltime job to a PRN job? Most importantly, what should be included in the resignation letter to an employer? Briefly mention why you decided to resign if you feel it's necessary.