Dear My Friend :
Today is my last day in XXX.
It is my pleasure to be part of XXX in the past years.
Also, thanks for your great effort for co-working in those past projects.
Pls kindly keep contacting if you need my help. Thanks.
我们公司，以及合作伙伴，不少同事last day的时候都会给工作中有接触的伙伴发一封告别信。 总结下来，大致如下：
farewell from XX （写你的名字）
Today is my last working day in XXX（公司名字）.
It is my great honor to work with you, to know you. I really cherish the time that we spend together.
Thank you so so much for your coaching, supporting and cooperating in these years.
Deeply wish you have a happy life!
Keep in touch via my personal contacts: