would a letter you write to your grandparents be different from a letter you write to a friend? how would the letter be different? write a few sentence about your ideas.

yes, it would have a slight difference because you would have a lot friendly chat with your friends than your grandparents because we show respect for elders. modify this answer! :)

A letter you write to your grandparents would most likely use more formal terms, because we are normally taught to respect our elders. A letter to a friend would be a bit more informal and you might write funny jokes in your writing, too.