The good news is that if you are foreign residents or a non resident of Italy you can be legally married in Italy. Also it's worth mentioning that civil and religious marriages are both recognised as legal entities in Italy. The local town and city Consulates and Embassies give information for citizens wanting to marry in Italy and travellers to Italy who are arriving specifically to get married should speak to the local Italian consulate where the marriage ceremony takes place, they will be able to help with the required documents and assist you. 

The paperwork that is required is not dissimilar to other countries, you need to have a valid passport or a proof of residence card and a stay permit -Carta di Soggiorno  or proof of recent entry to Italy. A few quirky additions are that you will also require  a declaration of no impediment issued by the national Consulate in Italy. This is confirmation of no obstacles to the marriage. All foreigners who want to get married in Italy must have this. For Italian people a "Certificate of Stato Libero"is required this declares that you are free to marry in the country, this is witnessed by two people and is available at an Italian Consulate outside of Italy or if inside Italy at the Pretura Civile  in the city where the marriage ceremony will be or through a notary (lawyer). You will also be required to show your birth certificate and this must show the parents names and in the case of a previous divorce a decree or annulment or death certificate with certified translations if they are not in Italian 

The civil marriage  

In Italy the civil ceremony is by an official of the Marriage Office usually the Mayor or his delegates at the Town Hall office. As is normal two witnesses must  attend along with family and friends if need be. An Italian speaker may also be requested at the ceremony to translate the process. Whilst the ceremony continues an official person will read the Codice Civile. The proposed couple will be read the marriage rights between them as future spouses. The finale is the declared announcement of the marriage. The Marriage Certificate is signed and names and details entered into the Marriage Register.

Religious ceremonies  

The most common in Italy is the Roman Catholic marriage. You do not have to have a civil ceremony because the priest has the ability to register the marriage within the civil registrar. All preparations should be made through the church. The documents that are required are similar to the civil wedding but you must also have a baptism and confirmation certificate to hand as well. The couple who are to be married must be confirmed and baptised and also attend a church premarital course.