Meaning: This sentence means that the female person is currently feeling joyful, content, or pleased. It's a way of describing someone's emotional state.
Choice of Words: "She" is a pronoun that refers to a female person. "Is" is a verb that indicates a state of being or existence. "Happy" is an adjective that describes a positive emotional state. When you put them together, "She is happy" means that the female person referred to is experiencing a feeling of joy, contentment, or well-being.