Pre-Production - Scripts

If you wish to have a character talking in the story, then they require dialogue. And for dialogue, an actor needs a script. A script is a written book of the story, with the actions and lines the characters would deliver. This gives the actor an idea on how to perform the character they are going for, and how they could deliver a voice for the character.
In this example below, we can see how a script should be laid out, making it easier to read for the actors. the text for dialogue should be aligned in the middle, separating the rest of the text which are the actions. the brackets in the dialogue illustrate the emotion or volume the character should deliver. In animation, only the dialogue is needed from the actors, but they still need to know how they should present it. acting it out can sometimes help them understand their character better, in order to feel more comfortable delivering dialogue.

source: http://filmschoolonline.com