The document discusses the two ways to say "you" in Spanish: tú and usted. Tú is the familiar form used with friends, family, children, and pets. Usted is the formal version used with strangers, older people, authority figures, and those just met. Usted is usually abbreviated as Ud. and capitalized. The choice between tú and usted can vary between countries but tú is generally used for God in prayer, while usted is safer to use initially until instructed otherwise.