What is doctype in HTML5? The doctype is not a HTML tag and Its provide the instruction to the web browsers about what version of HTML page is going to written(load). The <!doctype html> must be declare before the <html> tag and it's not case sensitive. The browser use this doctype information to render page correctly. The doctype not have the opening and closing tag like html. Share Get link Facebook X Pinterest Email Other Apps Labels doctype in HTML5 Share Get link Facebook X Pinterest Email Other Apps