I'm back from a month in Italy & wanted to share a quick tip for a few transit-related apps that were very handy in Rome:
1) URBI: To buy & validate ATAC bus/metro tickets online - all the different ticket types are available. It's very easy & intuitive to use, with option to use in English. I recommend downloading it and inputting your payment information before you plan to use it, so that you can purchase bus tickets on the spot. Once you've purchased, you can validate on board, using the app.
2) ItTaxi: To order the official white taxis in Rome. Works just like Uber/Lyft, orders a taxi to your location within minutes (or you can schedule ahead). It tracks your taxi arrival with the name of the taxi (each car has a unique name) and license plate number.
3) Rome2Rio: Travel planner. Despite the name, this app is not specific to Rome or Rio, it's global. But it helps you find the best route from Point A to Point B. Was very helpful for using public transport, offering various routes, including walking directions to get to & from bus stops. (GoogleMaps was also helpful in this regard, if you toggle to the Public Transport option. We used it in a small town (Pisciotta) to track the arrival of the town's lone minibus, which doesn't have designated stops.)