The head element contains information about the document.
Such information includes document's title, meta data with keywords, copyright information and many other valuable information...
The body element contains document's content.
Content can be any type of information served to user agents (browsers); i.e. content can be text, images and even audio based material.
Heading elements describe content's section and information it presents.
They are considered to be the titles and sub-titles of the content itself.
Hierarchy starts with <...
Address element supplies information about an author or authors of a document or perhaps a contact information.
A good practice is to add it at the beginning or the end of a HTML document.