So you made the decision to quit, and now you have to make it official. Writing a letter is the best way to make your resignation official, even if your company happens to be a little more informal. A letter, given to both your HR department and your supervisor, makes miscommunication unlikely and your intentions clear. So what should your letter say?
First, explain the reason for your letter, detailing any weeks notice and your general intention to leave. Next, if you desire, you can briefly explain the next step in your career path. For example, a statement as simple as “I have decided to accept another position” works just fine. Feel free to briefly mention that the decision was difficult but in your best interests (be honest).
It’s a good idea to give your assurance that you want to help your company make a smooth transition over your leaving, as well as thanking them for their time and opportunity and wishing them the best in the future. Ultimately, keep your letter brief and to the point, avoiding negativity or blame-placing.