Formal:
* 您 (nín): This is the most polite and respectful way to say "you." It's used for older people, strangers, or someone in a position of authority.
Informal:
* 你 (nǐ): This is the most common way to say "you" in everyday conversation with friends, family, or people you know well.
* 妳 (nǐ): This is the character used for "you" when addressing a female. It's less common than "你" but still considered informal.
Other options:
* 您们 (nínmen): This is the plural form of "您," used for a group of people you're addressing respectfully.
* 你们 (nǐmen): This is the plural form of "你," used for a group of people you're addressing informally.
Example:
* 您今年多大了？ (Nín jīnnián duōdà le?) (How old are you? - Formal)
* 你叫什么名字？ (Nǐ jiào shénme míngzi?) (What is your name? - Informal)
Remember that using the correct pronoun is crucial in Mandarin Chinese to show respect and avoid misunderstandings.