Greetings:
Hola
Buenos dias
Buenas tardes / noches
Saying good bye:
Adios
Hasta luego / pronto / mañana
Chau
Asking the basic question ‘how are you?’:
¿Cómo estás?
¿Cómo está usted?
In Spanish, you need to pay attention to whether you are in a formal situation or an informal one, as the words change depending on who you are talking to.