OK, great. But what is UI / UX?
User Experience Design (UX) is all about making sure a user feels happy. It focuses on usability, ease of use and pleasure provided in the interaction between the user and the product.
User Interface Design (UI) ensures the interface, it’s graphic elements, transitions and animations look and behave beautifully. It is a process of visually guiding the user through a product’s interface via interactive elements and across all sizes/platforms.
Here’s an awesome article about UI / UX from the Career Foundry if you would like to learn more.