Must vouchers be printed out?

I'm afraid the question is a little broad? Which cities? Which museums etc.?

It really does depend on the firm running the tour. To date, and I have traveled and used various tour groups in England/ France/ Scotland/ Spain/ Ireland/ Italy, etc., some of them have not even bothered to look at the printed ticket, they rely solely upon your name. Yet, here in America going to the Grand Canyon from Las Vegas, the driver was quite strict and adamant about collecting the voucher. Additionally, I have had them on my phone but for some reasons, the scanners cannot read them (Eurostar) so it is safe to carry the paper tickets with you.

Some sites allow you to use a smart phone and others don't. Without knowing which sites you're planning to visit it's really impossible to give any specific advice.

Donna

joealbanese, the OP isn't taking a tour. They are visiting Italy independently, and appear to be asking about general-entry tickets.

Donna is spot on that whether you can use smart-phone vouchers for pre-paid tickets or not depends on the attraction. If you are leaving TODAY, you may be too late for pre-booking tickets to the Borghese in Rome although you could try. That one tends to book up pretty far in advance. For everything else, you need to refer to the attractions' individual websites. If you DO want to sightsee one or more of the attractions with a private-company tour, you need to do the same.

If you have the time/money to make good of their prices, you might also consider purchasing tourist passes (e.g. Roma Pass in Rome; Firenze Pass in Florence, etc) but need to read the websites carefully to understand what they do cover and what they don't.

Vouchers are a common practice , across Europe , not just in Italy . One other good example is the Alhambra , in Spain . The printed voucher must be exchanged for an actual ticket prior to entry .

I agree with previous posters that practice varies regarding necessity for printed vouchers. I’d print them just to be safe. After all, paper is cheap and won’t add weight to your luggage 😉 and, for the security of knowing you’ll be admitted without problems, they are invaluable.

Be safe.

When in doubt, print it out!

One less thing to worry about, and they always take the printed voucher. Not true of the electronic ones in all cases.

I lost my printed vouchers at the Vatican, but fortunately we had hired a private local guide, and she knew who to talk to to get them to use my email on my phone. That may have still worked without her, but I was glad for her help for sure.