Pronto? — ready? — is how every Italian phone call starts, and it's used only on the phone. At work, you introduce yourself with your full name and company:

Italian	Meaning
Pronto, sono Marina Becker di Atlas Traduzioni.	Hello, this is Marina Becker from Atlas Traduzioni.
Potrei parlare con…?	Could I speak to…?
Con chi parlo?	Who am I speaking to?
Resti in linea, Gliela passo.	Please hold, I'll put you through (to her).
È in riunione. Vuole lasciare un messaggio?	She's in a meeting. Would you like to leave a message?
La richiamo più tardi.	I'll call you back later.
Scusi, La sento male.	Sorry, I can't hear you very well.

Gliela passo is Le + la: I pass her to you. For a man: Glielo passo.