A two weeks' notice letter of resignation is a professional courtesy and at times a contractual obligation. Here's how to let your boss know you're leaving.Basically, "a thank you to your current company for the opportunity" and "a departure date" two weeks from the email. A 2 week notice letter is an employee's letter of resignation to the employer. Clearly state your intention to leave and when you will be leaving. While it is traditional to have a two week notice, it is possible to give more or less time.