InVision is the digital product design platform used to make the world’s best customer experiences. In simple terms it is a prototyping tool created for designers, by designers. It allows you to quickly and easily create interactive mockups for your designs. When ready, you can share these mockups with your team or clients. It makes presenting your designs a breeze, and is much more effective than sending out a .PDF or screen shots. You can discuss the mockups right inside the app by leaving comments, that are connected to a point on the screen that you are discussing.It is a free tool. You can create the following.

• PROTOTYPE: Create Interactive mockup of a web, mobile or wearable experience.
• BOARD: Collaborative moodboard, brandboard, design story or collection.
• FREEHAND: Sketch, collaborate on design changes, or co-draw in real time.

Here is a live prototype: