I have resigned and am going to leave at the end of this month. I'm going to send a short message to my boss, telling him how to tell him politely, anything.

Situation 1, you have submitted your resignation application to your boss: since you resigned, your salary is not bad these days. To have a backbone.

Situation 2: You submitted your resignation to the human resources manager, but the boss doesn't know yet. Then you sent a message to the boss as you wanted, with the general content that you will leave at the end of the month. Life needs new goals. I don't think it is suitable to continue working in this position, and I need a change of environment. Thank the company and the boss for your cultivation. At that time, all you have to do is throw the end of the month to the boss. The boss won't bargain with you in those days.