What Else Should I Do When Resigning? First, out of respect and common courtesy, you would ideally tell your manager in person that you are resigning. If you can't wait for that or work remotely or some other complication prevents that, the telephone is the next best option. You can choose to follow up or accompany that discussion with a formal letter of resignation afterwards, but it would be a rare workplace that would require that formality.
Your End Date. The most crucial detail in a resignation letter is your end date. Legally and according to your company's policy, you might be required to give a minimum amount of notice (two weeks, or possibly more, depending on the company and the role). If that's the case, you don't want there to be any confusion about how much notice you give. If it's right there in writing in a letter dated two weeks before your last day, you're saving yourself the hassle.