Booking a train with trenitalia from Rome to Naples?

if you take a train called FRECCIA and you book in advance on line you will receive a mail confirmation containing PRN CODE once you get on the train the conductor needs only this code, not the ticket, you can print this email or write it on a paper if you take another kind of train you will receive the ticket by mail

hi, in addition to Fs, there is "Italo" trains, you get a code via email to be presented on the train, it is not mandatory to print the email, just a iphone Get the details on email www.italotreno.it www.trenitalia.com