It will be sent to you by March 31.
It contains only payments made in the period January 1 - December 31. For example, payments received in January, even if related to activities of the previous year, are included in the Certificazione Unica of the new year.
Also, if you are registered with the Chamber of Commerce, it is not produced. Effective from the 2024 tax period (CU2025), it is stipulated that the Certificazione Unica shall NOT be transmitted for forfettari Riders (Art. 3 of Decree-Law 1/2024).