Ciao! (THE MOST USUAL GREETING both for meeting and for farewell)
Pronto? / Pronto! (at the telephone, for example - ok?)
Salve! ( = Hi! )
If you mean how do they say hello? They say "Ciao" (pronounced chow)or you can say "buon giorno", "buona sera" "buona mattina" or "buon notte"
ciao
Ciao a tutta la famiglia
"Saluto"
Hello is Bonjour Colloquially - Ciao, Come stai? (Pronounced Chao! Komme stai)