UX is user experience, the discipline of making digital interactions useful, clear, efficient, accessible, and satisfying.
It matters because a website is often the first serious evaluation point for a buyer. Good design reduces confusion, builds trust quickly, supports accessibility, and helps visitors take the next step without feeling pushed.
Example
A UX review could ask people to find a service and request a quote without guidance. Observing where they hesitate helps identify unclear labels, missing information or unnecessary steps before deciding what to redesign.