Explain why you're leaving. Briefly explain the reasons you've decided to leave, both related to your current job and to your new position.A good resignation letter is a simple one. There is no real need to elaborate farther than you have to. Please accept this letter as a notice of my resignation. Use one of our resignation letter templates. You can pick a few classy reasons here. 1. Say you received a better opportunity for growth and position elsewhere. 2. Making a career change? Then you'll need to write a great resignation letter as part of the process.