Non-resident individuals who need to obtain a tax code can apply for it to the Italian consular authorities in the country of residence.

The tax code is issued by the Consulate through the computerized link with the Italian Revenue Agency and a certificate is given to the applicant.

Alternatively, the request may be submitted personally or through a person specifically delegated:

• to any territorial office of the Revenue Agency ;
• to the Operative Centre Pescara (Centro Operativo Via Rio Sparto, 21-65129 Pescara).

At the moment of the application, a valid identity card of the applicant must be presented. If the claim is made by proxy, the delegate must show a valid ID and a copy of a valid identity card of the applicant.
The documentation, as well as to prove the identity of the subject, must prove the legitimacy of the presence of the subject in Italy.
At the moment of the request, the Revenue Office issues a certificate of attribution.

Source: Agenzia delle Entrate