When we want to say hello (hola) in Spanish we can use different expressions as in many other languages but one thing to remember is that some expressions are more formal than others.
“Los saludos” are the greetings used in Spanish to say "hi” to someone. We can use the common “good morning” (buenos días), “good afternoon” (buenas tardes) and “good night” (buenas noches) to say hello to somebody in a correct manner as they are the most formal ways of saying hello to anybody.
We can also be a bit less formal and use some other expressions such as:
¡Hola!¿qué tal?, or ¡Hola!¿Cómo te va?
If it has been a while since you have seen the person that you speaking too, you can also say ¡Hola!, ¡Cuánto tiempo!
Have a look at the blackboard below to have a full description of all the Spanish greetings mentioned:
I'm a Spanish and English philologist specialised in Spanish linguistics and in teaching Spanish as a Foreign Language (ELE) as I love sharing my language, my culture and a particular vision of the world with people from around the globe, getting to know more about the world itself through them and languages.