Requesting a tax code at Philly consulate, which appointment option do I select?

I am in the beginning of a 1948 case and was told I need to apply for a tax code through the Philadelphia consulate. At the top of the page, it says tax code requests for non-Italian citizens can only be requested by mail upon appointment through Prenotami. On the site, I can book appointments for visas, passports, and citizenship. Which option is the correct one?