This paper will explore howto use new semantic tags in HTML5 (Hyper Text Markup Language) and how to structure document to create meaningfulhtml document outline. It will explore new semantic elements and cover changes in syntax of previous versions of HTML. Also it will describe HTML5 outline algorithm that helps defining and structuring site content. It willstudy statistics of naming html tags justifying the increasing use of HTML5 semantic tags as a standard in the structuring ofhtmldocuments.