* "Mālō le po" is the most common way to say goodnight, meaning "good evening/night." It's a polite and general greeting.
* "‘Ua lelei le po" means "the night is good" and is a more formal way to say goodnight. It's typically used in more formal situations, like when addressing someone of higher status.
You can also use "‘Ua lelei le taeao" which means "the morning is good," to say "good morning."