Basic HTML and HTML5: Declare the Doctype of an HTML Document

Basic HTML and HTML5: Declare the Doctype of an HTML Document
0.0 0

#1

My code does not work
this link for projcet:
https://learn.freecodecamp.org/responsive-web-design/basic-html-and-html5/declare-the-doctype-of-an-html-document

<!DOCTYPE html>
<h1>A cat</h1>
<html><h1</html>

#3

define your html tag before the h1 tag
also close the h1 tag which has been defined between html tag