Wireframes provide guidance for product development by extracting ideas from concepts and generating discussion. They keep designs loose enough for revisions while managing risks. There are two main types: low-fidelity sketches created with paper/pencil, and high-fidelity digital prototypes. Lo-fi wireframes aid brainstorming and guidance, while hi-fi are suited to explaining details to clients. Both should avoid unnecessary images or colors to focus on functionality. Effective wireframing breaks tasks into individual flows that can then be prototyped using tools like POP to test designs iteratively at low cost.