NIC.it is the Italian registrar that provides domains registration in the Italian country code Top Level Domain .it.
To start registering domains with NIC.it, you need to sign the Provider/Maintainer Contract with them and pass all the necessary procedures. To start your registration at NIC.it, please, visit the NIC.it website, go to the Provider/maintainer contacts page, then fill the Contract form and send it to the NIC.it Registry by post to the address specified on the web page.