If you're flying directly to Italy from India, your Declaration of Presence will be taken care of when you arrive at the airport. Only when you travel into Italy from another Schengen state, and stay with family/friends, do you need to visit the local Questura to report your presence within 8 days of your arrival.
The Polizia di Stato describe what your need to know about entering Italy:
Foreigners who stay in Italy for visits, business, tourism or study for periods not exceeding 3 months are not required to apply for a residence permit. Instead, they must report their presence in the country, following one of the procedures mentioned below:
aliens arriving from a non -Schengen country must report their presence to the border authorities and obtain a Schengen stamp in their travel document on the day of arrival. This stamp is considered the equivalent of the declaration of presence;
aliens arriving from countries which apply the Schengen Agreement must report their presence to the local Questura (central police station in the province) filling out the relevant form (dichiarazione di presenza), within 8 days of their arrival; for those staying in hotels or other reception facilities the registration form submitted to the hotel management upon check-in, signed by the foreign guest on arrival, constitutes the declaration of presence. The hotel will provide a copy of this form to the foreign guest who can show it to police officers, if requested.
As of August 8, 2009 a new bill (Law no. 94 of 15 July 2009) makes it a crime to enter or stay in Italy illegally. Therefore, foreign nationals caught entering or staying in Italy without permission commit the offence of illegal immigration, which is punishable by a fine ranging from 5,000 to 10,000 Euros. They are brought before the Justice of the Peace (Giudice di Pace) and repatriated. Hence, the Questore, after having expelled or rejected the foreigner, informs the Justice of the peace who passes a non-suit decision.