Questions

The polite form in Italian (pronome di cortesia ) for masculine and feminine in the singular is lei/Lei (you) and in the plural voi (you). The polite lei is usually capitalized, but this is not a must.

In Italy, especially in central and southern Italy, in spoken language, people tend to be on first-name terms with everyone or almost everyone.

If you want to address someone informally in a conversation, say "Possiamo darci del tu?" "Can we be on first-name terms?"

The forms signore (gentleman), signora (woman / lady), signori (gentlemen) and signore (ladies) are also used without surnames, e.g.: - Signore, prende un aperitivo? - Will you have an aperitif?

However, "Signor Rossi, prende un aperitivo?"- Mr. Rossi, will you take an aperitif?