HTML5 h3 Tag is useful to define and display third most imporatant heading of the page. Headings can have up to 6 level that includes h1 h2 h3 h4 h5 and h6
HTML5 h3 Tag Example:
<!DOCTYPE html> <html> <head> <title>HTML5 Tutorial</title> </head> <body> <h3>HTML5 Tutorial.</h3>
As you can see above, h3 tag is used to define and display third most important heading of the page.