UI - or User Interface - is a vital aspect to just about anything you’ll see on your device screen. It does require a certain amount of work, talent, and experience to create a successful UI design.
While it can be a difficult job, it is also rewarding for UI designers. Most have a background in art and graphics and enjoy the challenges and rewards that come with the career.
UI is definitely not something you can jump into and be an instant pro - but it is something almost anyone can learn if they put in the work.