This document discusses different types of letters and provides guidance on writing personal letters. It outlines the structure of a personal letter, including the sender's address, date, salutation, introductory paragraph, body paragraph, closing paragraph, complementary close, signature, and optional postscript. Some useful expressions are also provided for different purposes like gratitude, giving advice, delivering good or bad news, asking for help, and apologizing. Personal letters are meant to inform people we know and strengthen relationships.