I find it weird not being allowed to flag down a taxi on the street. In Rome, you must use a taxi stand, telephone, text, or app to get a taxi. This site has great information. The taxi stands are marked with an orange taxi sign and the taxis are always white. Some may be vans and some are in not so great condition, but they are always white. (Uber is only Uber Black which usually a luxury car and very expensive, and as I write this, maybe they have outlawed that as well.) There are lots of taxi stands all over the city of Rome but during these pandemic times, not all have taxis waiting around. The taxis have plastic barriers (well, most do) between the driver and the customers and generally the windows are open to help keep the air flowing. Everyone wears a mask. The base rate is €3 (three euro). Most rides around the center of Rome cost about 5-16 euro. No tipping although you can leave them the change. On regular city rides, the taxi driver will help you with your bags at no extra cost. Generally the drivers don’t speak English. If I can’t explain where I want to go, then I show them on my phone.
If you use an app like ITaxi (Italy Taxi) or Free Now, you can get a taxi anywhere you happen to be. The taxi meter starts when they ACCEPT the ride, not when you get in the car! This is what is shocking to most foreigners. Most of the rides I’ve taken have started at about €4.40 by the time I got in the car. This also means that the taxi will wait for you. It’s on you and not them. So it’s easier for me to get them show up. It is possible to pay by credit card and the drivers never have change for a 50. (Also, they have a color rating system for customers… one day I read the phone screen of the taxi driver and I could see my name and that I was “gold” level.) It is also possible to call or text to request a cab, but I prefer the app. I just wish that I could input the name of a restaurant instead of an address.
Airports: The rates from and to the two main airports, Leonardo da Vinci–Fiumicino Airport (FCO) and Ciampino International Airport “G. B. Pastine” (CIA), are set to the Aurelian walls of the city. But, then it’s metered so while the base cost is 48 and 30 euro, it will cost you more. Tell the taxi driver that you want the set price so that at least that is a known quantity. From Fiumicino, a taxi ride to the historic center of Rome will probably cost in the 50-60 euro range (ride is about an hour) and from Ciampino (ride is about half an hour), from 30-40 euro. Plus extra for extra luggage.
Although you can walk everywhere in Rome, there are a lot of hills and groceries get heavy… Of course, people do flag down taxis on the street… but you are not supposed to.