A declaration for entry MUST be filled in by anyone coming back to Italy after a stay in another country.

Foir further information: https://www.esteri.it/mae/en/ministero/normativaonline/decreto-iorestoacasa-domande-frequenti/focus-cittadini-italiani-in-rientro-dall-estero-e-cittadini-stranieri-in-italia.html