Web design is a practice that combines the improvement of the User Interface (UI) and User Experience (UX) of a web app or website, in order to deliver the best product possible. Not to be confused with software development, web design focuses on things like functionality, usability, and appearance.

The user interface is the graphical layout of the web app. UI consists of color palettes, fonts, images and other elements the user interacts with on the web app. All of the visual aspects should be cohesive, both aesthetically and functionally. They should be suitable for the web app and the brand it represents. 

The most significant task of UI designers is creating an attractive and aesthetically appealing interface that is accessible and designed for potential customers.

UX is a process designers follow to develop services and products that ensure a positive user experience. The experience should be seamless and easy, giving customers the impression that they have finally found what they're looking for. How simple or difficult it is to engage with the user interface, determines the user experience.