The main element represents the main content of the body of a document or application. -w3c
The <main> tag in HTML represents the central topic or core content of the document body. It is a semantic and structural element introduced in HTML5.
<body>
<!-- Other content such as header, nav -->
<main>
<!-- main content of the document body -->
</main>
<!-- Other content such as footer -->
</body>The <main> element is also useful for screen readers to skip the navigation and other irrelevant content and jump directly to the core content of the document.
A document should only contain a single <main> element.