1st Time to Italy

Are you male or female? What time of year? For how long? What part of Italy? Any activities like hiking or beach time? Packing lists for different parts of the world in different seasons abound on the web. Or you can start here: https://www.ricksteves.com/travel-tips/packing-light

https://www.ricksteves.com/watch-read-listen

I'd suggest your reviewing the above and getting an RS Guide book. Your question is too broad to attempt to answer. Once you have a general itinerary, timeframe, and season, it will be easier to help you.
Safe travels.

Hi there and welcome! For more detailed info after you've answered the above questions for yourselves, consider the time of year and have a scroll through some of the Forum's great packing reports here. https://community.ricksteves.com/travel-forum/packing.

Here's a good start to packing light by forum members - https://community.ricksteves.com/travel-forum/packing/any-tips-on-packing-light

And if you want to be inspired about how to pack very light, Jean is taking less than 12 LBS for a 3 week trip to Italy! (Not suggesting you do this, but just to see what a range of styles is out there.) If you know little about overseas packing and plan on taking trains, remember you have to CARRY this stuff up and down stairs, etc! https://community.ricksteves.com/travel-forum/packing/ultralight-packing-appreciate-any-ideas-to-drop-it-further-down.

Good luck and come back with more information about time of year, how many destinations, mode of travel etc.

What not to pack:

1. Red MAGA cap
2. Wife-beaters
3. Any clothing with "I hate Italy" graphic
4. Any clothing with "Olive Garden" graphic
5. No swastikas, please
6. Confederate flags also probably a bad idea
7. Hair dryer with US electric plug
8. Lacrosse gear

Something with sleeves or a shawl for visiting churches and historic buildings.