My husband & I will go to Canada for working two years and then come back.
My daughter will come with us and continue the study in Canada.
I need to write a letter to my daughter's school principle to inform him about it.
Also, I want my daughter can continue the study in his school after we come back two years later.

Can anyone kindly help me to draft a formal letter??
A lots of thanks!!

(from Hong Kong)
Hi, Calamus.
Formal letters have different styles in different countries. I'm from the UK, so can only tell you what I would write.

Dear _____________,

I am writing in reference to my daughter, ________________.

My husband and I are moving to Canada and our daughter will accompany us. We will leave on (date) so our daughter's last day at school will be (date).
While in Canada she will be attending school/college at (name of school/college).

We will be returning in two years' time and I would like to enquire if it will be possible for my daughter to re-enrol at your school/college upon our return.

I an waiting for your reply,

Yours sincerely,