Are they at taxi stands, or can they be hailed on the street? I don't remember from my last visit 12 years ago, although I know we used them a couple of times!
Taxi stands but you might get lucky on the street. Taxi stand is preferred.
A taxi driver stopping for hailing tourists is breaking the rules, don't trust him for anything else.
Go to the taxi stand or you can use an app on your smartphone to "hail" a taxi to your door. With the latter, you pay from the moment the taxi leaves the stand on their way to you. https://it.mytaxi.com/index.html
Of course any hotel or restaurant will be happy to call a taxi for you or direct you to the nearest stand.
This is also a very useful artcile https://sites.google.com/site/sctappromeforcruisetravelers/contenuto-della-app/about-rome/using-taxis-in-rome.
Laurel, thank you for the taxi info link. It’s very help since I will be taking a taxi within Rome to change hotels.
My thanks, too, Laurel. Now I have all the info about Roman cabs I need!