In English, we typically use the word ‘Romans’ to refer to the inhabitants of the ancient city of Rome and the citizens of the Roman Empire. It feels a little strange to use the word to refer to the modern-day inhabitants of the Italian capital. We’d probably say something on the lines of “He’s from Rome,” or “It’s a style seen in Rome.”
However, in Italian, it is perfectly common to use the word ‘romano’ or ‘romana’ to refer to a native of the city of Rome. Just as a ‘milanese’ is someone from Milan or a ‘fiorentino’ is someone from Florence, a ‘romano’ is a person from Rome, i.e. a ‘Roman’. Now, to refer to the ancient Romans, you would still use the same word. So, ‘the Romans’ would simply be ‘i romani’, but your listeners or readers would have to know from context that you are referring to ancient Rome and not the modern one.
In Italy, the place where you are born is the place with which you will generally be identified when people talk about the part of the country you are from. If you are a ‘milanese’ and move to Rome, you typically do not become ‘romano’, even if you live there for the rest of your life. You might say “Sono milanese ma vivo a Roma da trent’anni.” (“I’m from Milan but have lived in Rome for thirty years.”). In other words, these labels do not identify where a person is living but where their roots lie.
By the by, note that you say “vivo a Roma”, not “vivo in Roma” as you might in English. You only use “in” for a country or region. For example, “I live in Genoa, which is in Italy” is “Vivo a Genova, in Italia.”
Coming back to the subject of Romans, whatever you do, make sure you do not call anyone from Rome a ‘romagnolo’, as that is used only for natives of the region of Romagna in the north-east. This forms part of the larger administrative region of Emilia-Romagna. Someone from Emilia, is, of course, an ’emiliano’. Now, ‘romagnolo’ can also refer to the local Italian dialect of Romagna. However, the local dialect of Rome is not ‘romano’, but ‘romanesco’.
Finally, two more words that do not describe any Italians at all. ‘Romeno’ (with an ‘e’ instead of an ‘a’) is used to refer to Romanians, i.e. people from the modern-day country of Romania. Do not call someone from Rome a ‘romeno’. Then, there is the word ‘Rom’, which refers to gypsies. You will often see the phrase ‘i Rom’ (‘the gypsies’) in newspaper articles about them.
In Italy today, you can find romani, romagnoli, romeni and Rom. Good luck! 🙂