How do you get to Italy?

Depends on where you're starting from, how fast you want to get there, and how much you want to spend. Italy is in Europe, so if you're on another continent it'd probably make most sense to fly.
There are several large cities you could fly to, including Rome, Naples, Venice, Milan, and Turin.

If you take a cruise, most will arrive in Rome/ Ostia/ Civitavecchia or Palermo in Sicily.