Header
The <header> element represents a container for introductory content or a set of navigational links. A <header> element typically contains: one or more heading elements (<h1> - <h6>) logo or icon.
Body
The <body> tag defines the document's body. The <body> element contains all the contents of an HTML document, such as text, hyperlinks, images, tables, lists, etc.
Sidebar
The aside element represents a section of a page that consists of content that is tangentially related to the content around the aside element, and which could be considered separate from that content.
Footer
The <footer> tag defines a footer for a document or section. A <footer> element should contain information about its containing element. A <footer> element typically contains: authorship information.