Use this termination goodbye letter to discuss job references after being fired.
Thank you for the opportunity to work and learn here for the past {number} years. Although I understand that I was not the best fit for you here at {Company Name}, I'm grateful for the experiences.
I would like to arrange a meeting with you to discuss my termination from the company. Specifically, I would like to ask you about ways I can move forward toward looking for another job, and whether or not I can use you or {other supervisor's name} as a reference.
I wish you and {Company Name} the best of luck in your future endeavors.