How do you write a letter to your friend in another telling him or her about the preparation your school is making toward 20th anniversary celebration?
Here is an example since I dont know how to explain your question to you in simple word form without an explanation..
Dear [insert name],
The school is making a [big or small] preparation for the schools anniversary! For it being the schools 20th anniversary, yes the 20th, the school is [explain what the school is doing].
Since [name your school if you would like] (place it here if you didnt name your school) is doing this celebration, I just wanted to let you know about it. The whole school should be there, I [dont know if I] am going, but I will let you know. Just think of all the times other students [and me] complained and how long the school has listened to their students complaining!
Here is to the schools 20th,
[However you end your emails]
I apologize for not being able to explain it, but I hope that example helps a bit, I couldnt go further into detail into it without the information but you can do that yourself. Good luck with your email to your friend, whoever that may be, and have a good time at the celebration if you are/can going!