To write a character questionairre novel, start by outlining your characters thoroughly. Know their backstories, motivations, and quirks. Next, come up with a questionnaire that will dig deeper into these aspects. You can have the characters answer these questions directly in the story, or use the questions as a tool to guide their actions and decisions. For instance, if a character's question is about their greatest fear, their actions in the face of danger can be shaped by that fear. Also, make sure the questions are not too obvious and keep the flow of the story going smoothly so that the questionnaire aspect doesn't seem forced.
First, create interesting characters with distinct personalities. Then, design a set of questions that can reveal different aspects of these characters, like their goals, fears, and secrets. Incorporate these questions into the plot in a natural way.