To start the conversation
This is….
Could I speak to … please ?

To answer
Who is speaking please ?
Who’s calling ?
Hold the line…
I can take a message…
I can put you through…

To end a call
Thanks for calling
Good bye
Speak again soon
To hang up ⇒ To end a call
To put on hold ⇒ To temporarily pause the call
To leave a voicemail ⇒ To leave a message (if someone does not pick up the phone)
To take a message ⇒ To note down a message for someone