Answer:
In a book you'd represent dialogue by starting a new paragraph when someone starts to talk, and adding qoutations. sometimes people just put the conversations in italics, or use " ' " (The small line in the middle.) And example would be like this:
"Jenna, can you call me tonight?" Suzie asked.
Jenna hesitated. "No, I can't. Sorry." she replied.
"Please? I really need to talk to you!" Suzie insisted.
Like that. ^^ Hope I helped :D