The Vatican City is a city-state surrounded by Rome. Its the smallest country in the world, home to the Pope and a must-see for anyone visiting Rome.
Getting to the Vatican by public transport is easy. The Rome Metro has a station just outside the Vatican walls at Ottaviano-S. Pietro. Line A of the Metro runs through with trains every few minutes. It’s then a 5-minute walk to both St Peter’s Square and the Vatican Museums. There is also a train station, St Pietro, which is also a 5-minute walk from the Vatican.
If you wish to walk, it is a very pleasant and easy walk from the main sights of Rome. The Vatican is located just 15-20 minute walk from the heart of the city centre.
If the Pope is in residence, on Sundays at noon, the pope appears at the window to pray and bless the crowd in St Peter’s Square. No ticket is required but expects long lines. We highly recommend you bring water, snacks and a sun-hat, especially during summer as there is a lack of shade.
St. Peter’s Basilica dominated St Peters Square and is a must visit. It is free to enter the main St. Peter’s Basilica, though there are admission fees for a few parts, such as climbing the cupola and the Vatican Treasury. St Peter’s Basilica is open daily, April-Sept 7am-7pm and Oct-March 7am-6pm.
The Vatican Museums are open Monday to Saturday and closed Sundays. There is a charge to enter the museums and you can pre-buy tickets on the Vatican Museums website.
I recommend the Rome Toolkit website which has information on everything you need to know about the Vatican and Rome. https://www.rometoolkit.com/whattodo/vatican_stpeters.htm