The Reporting your presence is required in Italy, which the host must comply with.
The likelihood is high that they are asking for the passport image beforhand so that they can fill out the form (twice) so that all you have to do is sign it upon arrival.
If you don't want to do this, print out the corresponding form, fill it out properly and tell them that you will give to them upon arrivel.
(or send them all the information asked for in the form)
The host may/must want to varify the data contained in the form against your passport/ID.
for those staying in hotels or other reception facilities the registration form submitted to the hotel management upon check-in
For EU-Citizens this is not strickly required, but...
If they decide not to report their presence, they will be deemed to stay in Italy for a period exceeding three months, unless proven otherwise.
Each form has 2 sides, where you must fill out the same information
- the second is intended for you as proof of registration
The hotel will provide a copy of this form to the foreign guest who can show it to police officers, if requested.
European Union citizens
Reporting your presence
Union citizens or their family members, depending on the length of their stay, can report their presence to a police office, filling out the relevant form ('Declaration of presence' for Eu nationals). If they decide not to report their presence, they will be deemed to stay in Italy for a period exceeding three months, unless proven otherwise.
Hence, EU citizens who intend to stay for less than three months are not subject to the obligation of reporting their presence or to any other formalities.
If they do not report their presence in Italy, they must be able to prove that they have not stayed in Italy for longer than three months.
In case they cannot provide any evidence of their entry, they will be deemed to stay in Italy for a period exceeding three months.
If they decide to report their presence, they need to follow the procedures set forth in the relevant decree by the Minister of the Interior. Until the decree is issued, they can report their presence to the local police office, filling out the relevant form.
Foreign nationals [non EU-Citizens]
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.
The original text link is faulty (Link to form for EU-Citizens)