The difference between UX and UI can be summed up in one word: intangibles. UX refers to the user experience, which includes all the intangible factors that make using a product enjoyable, such as the overall look and feel, the level of customization, the ease of use, etc. UI, on the other hand, refers to the user interface, which is the tangible way users interact with a product, such as the buttons, the drop-down menus, the search bar, etc.
In other words, UX is about how a product feels, while UI is about how a product looks. Both are important in creating a successful product, but they serve different purposes. UX is focused on the overall experience of using a product, while UI is focused on the specific details of how that product is used.
A good UX designer will take into account all the different ways a user might interact with a product, and design the experience accordingly. A good UI designer will create a visually appealing and easy-to-use interface that matches the UX design. Both roles are important in the product development process, and both require a different set of skills and knowledge.