The call to action in a persuasive essay is a portion of the conclusion that appeals to the reader to take action related to the essay's topic. A call to action is often used in persuasive speech as well.
The main body of the essay sets up the introduction, provides information and generally educates the audience on the subject being written about. Before the call to action is reached, common objections should be addressed to make a stronger argument for the writer's position. The conclusion, which contains the call to action, is used to lay out and highlight the different actions that are available to the audience or reader.