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You have decided to leave your current employment. Write a letter to your employer. Include the following in your letter:
– Explain why you are writing
– Explain why you have decided to leave the company
– Tell your employer what you plan to do after leaving your present employment

Dear Mr. Zhang,
I am writing to inform you that I am planning to leave your laboratory due to a personal reason. I have booked a ticket for 12th of January 2018 and will stop working from one week before my departure.
Let me explain my situation in more detail. I have been trying to get permanent residency of Canada since last year and finally I could make it. I strived a lot to achieve it by studying English very hard and improving my qualities. Although working in your laboratory was a golden opportunity for me to get valuable experience, I do believe that by immigrating to Canada not only I can develop my skills but also I would have better job prospects. Furthermore, due to high standards of living in Canada I suppose that my children would have access to higher level of education and they can also improve their English proficiency.
After moving to Canada I am thinking of getting a scholarship to get a master degree in university of British Columbia. Thereafter, I will try to find a position in a private company to improve my practical experiences to open my own company afterwards.
Please let me know.
Sincerely yours,
Samad

Samad, this is a nice piece of writing. A couple of suggestions:

Dear Mr. Zhang,
I am writing to inform you that I am planning to leave your laboratory due to a personal reason. I have booked a ticket for 12th of January 2018 and will stop working from one week before my departure.

You have given notice above but also included a partial explanation. It's clearer to leave the reasons for the next paragraph. Also, "am planning to leave" is a little unclear - almost as though you are still considering whether you will leave. Better to state clearly that "I have decided to end my employment at your laboratory". Finally, "I have booked a ticket" is rather vague, so better to state that I will be leaving the country on..."


A few other edits in capital letters below:

Let me explain my situation in more detail. I have been trying to get permanent residency of IN Canada since last year and finally I could make it AND HAVE FINALLY SUCCEEDED. I strived a lot to achieve it by studying English very hard and improving my qualities I HAVE WORKED VERY HARD TO IMPROVE MY ENGLISH. Although working in your laboratory was a golden opportunity A WONDERFUL OPPORTUNITY for me to get valuable experience, I do believe that by immigrating to Canada not only I can develop my skills but also I would WILL have better job prospects. Furthermore, due to high standards of living in Canada I suppose BELIEVE that my children would WILL have access to A higher level of education and they can also improve their English proficiency.
After moving to Canada I am thinking of getting a scholarship to get STUDY FOR a master "Masters" degree in university AT THE UNIVERSITY of British Columbia. Thereafter, I will try to find a position in a private company to improve my practical experiences. EVENTUALLY I HOPE to open my own company.
Please let me know. THIS IS NOT NEEDED - YOU ARE NOT ASKING PERMISSION. (Better to state that you wish him every success in the future).
Sincerely yours,
Samad