Italy uses Type L plugs (3 round pins in a line — unique to Italy) plus Type C (2 round pins, standard European) and Type F (2 round pins with earth clips, German-style). Voltage: 230V / 50Hz (vs 120V/60Hz in the US). Your phone/laptop charger almost certainly works (check the label: "INPUT: 100-240V" means it's universal). Your hair dryer probably doesn't. Bring a universal adapter, not just a European one.
Best option: Universal travel adapter (€10-15 on Amazon) — covers Type L (Italy), Type C/F (rest of Europe), Type G (UK), Type A/B (US). Why not "just European": Standard European adapters (Type C — 2 round pins) work in MOST Italian outlets but NOT the older 3-pin Type L sockets found in many hotels, apartments, and older buildings. A universal adapter with the Italian 3-pin option solves everything.
SAFE (dual voltage, 100-240V): Phone chargers, laptop chargers, tablet chargers, camera chargers, electric razors. Check the label on the charger brick — if it says "INPUT: 100-240V" you're fine. NOT SAFE (single voltage, 120V only): Most American hair dryers, curling irons, straighteners. Using a 120V device on 230V will burn the motor out (sometimes with sparks and smoke). Solution: Buy a travel hair dryer (dual voltage, €20) or ask your hotel — most provide one. Voltage converters: Heavy, expensive, unreliable for high-wattage devices. Not worth bringing.