UX design is all about the user experience rather than visual design elements. UX design principles cover the functionality of applications and how this functionality affects user experience. User Interface design principles, on the other hand, cover the visual elements with which the user interacts when using an application.
There are many online courses for UI and UX design that cover both user interface and user experience principles in very general terms. However, if you are looking for a high-quality software design/UX online course that focuses specifically on User Experience design principles and skills as well as real world experience, our Upskiller course is the one to choose.