Dialog show how a character speaks so you can see the level of education and regional area where he or she lives.
It's prose.
dialog
Dialogue is what the character(s) is/are saying.
Your question is a format question. Your publisher will advise you about how dialog is best presented in fiction. Preserving the script format for dialog in a fiction story may be too wasteful of space.
It depends on what sort of book you're writing. There can be dialogue if it's a fiction book. A nonfiction book usually does not contain dialogue.
insert a dialog choice a couple times into the dialog
how to make a short dialog
Dialogue is essential in fiction because without it, you've got a dull, boring story. You can learn all about characters through the way they speak.
dialog
Health Dialog was created in 1997.
Troika Dialog was created in 1991.
Dialog TV was created in 2005.