The Italian Government has issued a new ordinance with regards to covid rules and regulations.
With regards to travel the rules are in place until November 26th 2021
You can enter Italy from most countries, you just need to fill in a Passenger locator form and not have symptoms of covid-19 and be double vaccinated.
If you are from a List D or E country you will need to present a negative covid test taken with 72 or 48 hours depending on the country (The UK it is 48 hours) of your entry to Italy. You entry to Italy means the time you land in Italy, hence taking it the day before is advisable. You can use rapid antigen tests.
Covid-19, travellers (salute.gov.it) Is the official Italian Government Advice Website for Travellers in English with the rules.