Trenitalia

Maureen, I don't know the difference but I do know that all you need to do is check without invoice and proceed. I've purchased tickets twice this year and everything has been fine by checking "without invoice".

Larry, thank you. In the case of "no invoice" did you still receive an email response with all necessary information for your reservation? And if so, could you board the train directly with that email? Again, thank you.

I don't recall the invoice issue when I got tickets. I purchased Milan to Venice and Venice to Florence tickets online. Shortly after I received a email from trenitalia with a pdf of our tickets. I printed those off. It has the train number, times and your seat and a scan code area. Now to use them next week.

Maureen, in both cases this year, I did immediately receive an email with the tickets. One ticket was from Venice to Florence. It has the 6-digit PNR number on the paper. This is your ticket and you can board with it. The second ticket was from Rome to Assisi with a train change at Foligno. One train was a train requiring seat reservations. Again, this ticket had the PNR number. The second train was a Regionale train. These tickets for a Regionale do not have a PNR number. Instead they have an 8-digit Ticket Code number. Since the second ticket was combined with the first train, it was pre-validated and I could board the Regionale without any further things to do. I am registered with Trenitalia and I've had no problems getting tickets for a few years.

Larry & Robert, You have both been very helpful. Thank you so much. I love this helpline!

Indeed there are some great people in this helpline. They've answered a bunch of my questions.

Maureen, From reading the Trenitalia website, I think it means that if you 'without invoice' you will receive a paper receipt on-board from the conductor once he enters your pnr info into his scanner.
If you 'with invoice' your purchase receipt is emailed to you.

I pushed the "within voice" button to see what would happen. It had lots of complicated details that are probably for business travelers who need to document their travels. You definitely do not need it to have a valid ticket. The ticket itself has a data matrix code the conductor will scan. Make sure to register on the site before purchasing. That way, in the off chance they do not send the email, you can always find a link to a PDF with your ticket by logging in to your "customer area.". Also, do not choose the option to receive the ticket by SMS (text to your phone). Then you will NOT get an email.