Question

Why the HTML structure is important to properly written in HTML document

Answer 1

The browser understands it, if you don't add the thing, you maybe can't access other files.

Step-by-step explanation:

Answer 2

A properly written HTML document will not only be readable to the user, but will also convey the structure of the document, the relationship of its content to each other, and allow the user to link to other pages and sites. HTML can do all of this because it's a markup language.