Hi LJ. Just a few things you need to correct in this piece. Here they are
I will introduce my family. My name is LJ. I am 16years old. When I was young, I lived in Seoul with my grandparents and my parents and my sister. My grandmother’s name is Kyeong Hee. She is very beautiful and nice. She likes me very much, so nowadays my grandmother is sad, because I stay in Phuket. She wants me come back early. She has a house, so we live the same house. My grandfather’s name is Dong Soo. Also he is very handsome and nice to me, but he died in 2001, so I was very sad during 1year. My mother’s name is So young. She is very pretty and nice to me, also nowadays she is sad, because I stay in Phuket. My father’s name is Sang Won. He is blunt to me, when I was young, I didn’t like my father, but now I like very much. My parents have the Korean restaurant. My sister’s name is Yoo Jin. She is very cute and kind to me. I love my family very much.
I will introduce my family. – Nothing grammatically wrong here but I think you need to make a better introduction. This is very short and blunt.
My name is LJ. I am 16years old. – Join these sentences together using a conjunction (and)
I am 16years old. – need a space
When I was young, I lived in Seoul with my grandparents and my parents and my sister. – … , … and …
She likes me very much, so nowadays my grandmother is sad, because I stay in Phuket. – Get rid of the comma
She has a house, so we live the same house. – Tense, Need a Preposition
She wants me come back early. – to come back early.
Also he is very handsome and nice to me, but he died in 2001, so I was very sad during 1year. – Tense, need a space
She is very pretty and nice to me, also nowadays she is sad, because I stay in Phuket. – Runon sentence
He is blunt to me, when I was young, I didn’t like my father, but now I like very much. – Tense, Runon sentence
My parents have the Korean restaurant. – Article (‘a’, not ‘the’)
Good work on this. Make the changes quickly because you have a lot of other work to do. When you have made the changes, delete this post.
Mr Andrew