Companies: VAT ID or Tax ID from the company in the European Union, Iceland, Liechtenstein, Norway, Republic of San Marino, Vatican City or Switzerland, or Codice Fiscale from the company in Italy. 

Individuals: Passport or ID number from a European Union member country, or Italian Codice Fiscale.

Anyone and any company can register this

The minimum term for .bz.it domain names is 1 year

The minimum term for .bz.it domain names is 1 year

Domain Names must:

• have minimum of 3 and a maximum of 63 characters;
• begin with a letter or a number and end with a letter or a number;
• use the English character set and may contain letters (i.e., a-z, A-Z),numbers (i.e. 0-9) and dashes (-) or a combination of these;
• neither begin with, nor  end with a dash;
• not contain a dash in the third and fourth positions (e.g. www.ab- -cd.bz.it); and
• not include a space (e.g. www.ab cd.bz.it).

You may visit them here: Registro.It.