Author's Purpose

An author writes about ta new video game. What is the author's purpose?

The author tells you about the history of China. What is the author's purpose?

An author writes a story about a cat chasing a mouse in an amusement park. What is the purpose?

An author writes about why you should join the baseball team. What is the author's purpose?

An author writes why you should vote for a certain person for president.  What is the purpose?

An author writes about his kite getting stuck in the trees. What is the author's purpose?