While "Buenos días" (good morning), "Buenas tardes" (good afternoon), and "Buenas noches" (good evening) are also used, "Hola" is the most versatile and widely used greeting.
While "Buenos días" (good morning), "Buenas tardes" (good afternoon), and "Buenas noches" (good evening) are also used, "Hola" is the most versatile and widely used greeting.