Military records are a wonderful way to find out information about a person. Generally the Italian records valuable genealogical information such the name of the person, his age, birth date, place of birth, parents names (mother’s maiden name) and a full physical description of him. More information can be found here: Military & Conscription Records.
Here are some examples of Military Draft Cards and Conscription records.
If you’re ancestors were from Northern Italy and you are looking Military Records from Venezia you may want to give the Archivio di Stato di Venezia search a try. Please note: The site is in Italian.