A hero section is the prominent opening area near the top of a webpage. It is like the front sign of a shop: it quickly tells visitors where they are and what the place offers.
It often includes a short heading, a sentence about the product, and one clear next step. A service page might say what the service does and offer a button to try it.
Make the main message understandable before adding decoration. A hero does not need to fill the whole screen; it should help visitors decide whether they are in the right place.