Just structure. All elements and content shown as they should look like. Main info. Simple, usually colorless, just like wires. You can use colors to show what is more important or what user can click. Fast, cheap.
Wireframe with some interactions. To test the product. What will happen when you click here and what you can do next.
Visual representation. How it will look on different devices. Static, no interactions, just beautiful.
And still NO coding at all.