Prototypes are one of the most critical steps in the design process. The goal of a prototype is to test our ideas before sinking lots of time and money into the final product.
Prototyping is essential for resolving usability issues before launch. It can also reveal areas that need improvement. Once a draft of your product idea is in the hands of real users, you’ll finally see how they want to use the product. You can then go back and adjust your initial guesswork.
The actual form of the prototype can be paper or HTML and desktop. The fidelity of the prototype doesn't have to be high-fidelity, but as long as it gives you new insights into how people will naturally use the product, it doesn’t matter whether it is paper, low-fidelity, high-fidelity, or HTML.
Prototyping is inexpensive, fun to make and can be kept as a reference for future iterations. There’s no one, best process for prototyping, but some are better than others. Below are some examples of lo-fi digital prototypes: