What are the meanings of the tags header, nav, section in html 5? Is it better to use these tags rather than creating?

Answer 1

These tags are implemented into HTML5. It structures the website the same way as <div> would do. They are used for better SEO so that's biggest reason why you should use them over <div id="header...">. Same as with <div>, your site will get design through CSS. So yeah, not big changes brought by those new tags :)

Answer 2

https://www.w3schools.com/html/html5_semantic_elements.asp

Answer 3

obviously better , beacuse for a site creation and Crawl by the Google search engine you need to have valid HTML pages, where it is tested by www.w3validator.org .Would be better if you use valid HTML,so that there wouldn't be any breakups if at all the browser has got updated