Good UI design supports usability, give clarity and help users understand their options in a given situation. It shows the brand identity and gives the product the right "look and feel".
The UI design also includes the design of micro-interactions such as animations, transitions, interactive behaviors etc.
The final design is documented in detail, so the development team can start building it. We deliver a complete design specification containing a visual representation of all screens, a style guide, as well as a description of the interaction design and user interface guidelines.