User Interface (UI) is the point of human-computer interaction and communication in a device, system or software. Coursera's UI catalogue educates you on the principles of creating intuitive, user-friendly interfaces. You'll delve into the fundamentals of visual design, interaction design and information architecture. The skill set includes learning to design wireframes, prototypes, and fully functional user interfaces using various tools and frameworks. You'll also grasp the principles of human-computer interaction (HCI), usability testing, and accessibility, enhancing your capability to create engaging digital experiences across various platforms.