HTML5 introduced semantic elements. In the past html elements were split by <div> and <span> tags normally with a class or id to describe the purpose. Sematic HTML tags changes this as HTML since HTML5 now has a selection of tags that are used to describe the meaning of the content of the page. The elements that were added to HTML5 were chosen to be a subset that meets the demands of the web Common tags include <nav> for page navigation blocks, <header> and <footer> for headers and footers, <article> for elements which are to be read alone and <aside> for side elements inside other elements.
Semantic HTML elements make HTML easier for us to read and understand what the parts of a webpage are doing. The sematic elements also make it easier for programs that read web pages wuch as spiders and crawlers to read pages and decifier where the meaningful information is.