Hi Ra Mi, welcome to EF! :)
I would like to modify and rewrite your letter completely because the format of your letter is quite messy. You've neglected some important points in writing a letter, especially punctuation marks.
Dear Mr and Mrs John
Dear Mr and Mrs John,
I'm YoungMy name's Young and I
come from Korea.
Today, iI am writing write
this letter to
thanksexpress my gratitude for allowing
me to stay with your family when I am going to
live and study ...
I'm 16 years old, and I
study at Seoul High School. I live in Korea with my family, particularly my
father, mother, and my
younger brother. My father is a businessman, my mother works at her shop, and
my brother is still
5 years old, so that
to school yet
In free time, I like
listening to (...) shopping with my friends. I also
like watching films, so I often
go to the cinema.Next month,
while I'm studying
there, I want to
study hard and
improve my English.
On the other hand. i'mAlso, I am
ready to discover a
beautifulwonderful countrycity like New York.
i'llthat it would be exciting to have with
a new life in New York. After finishing
universitymy undergraduate study
, I want to
a businessmen like my father. That's one of my biggest dreams
I hope we
lives happy and has memorables together.can live happily and share many memorable experience together.
Ra Mi Young
As you can see, Space, Capitalization, and Punctuation marks are really important. Good luck in revising this letter :)