Leaving a job isn't easy. To write a short notice resignation letter, include your position and effective date, explain your reason and express gratitude.We've rounded up tips and examples for writing a resignation letter that'll help you maintain work relationships long after leaving a company. It's a short, formal, and friendly letter that announces you're leaving the company and your current role. In the body of the letter, immediately state your intention to resign and provide your reasoning, including only positive feelings towards your work experience.