What is the correct way to declare an HTML5 Doctype.

Question

What is the correct way to use start tag when creating with HTML5

IE: HTML 4 Strict is like this

Answer 1

The clearest most definitive answer of what the standard says seems to be for HTML 5.3 at:

http://w3c.github.io/html/syntax.html#the-doctype

Note especially the list-items 1 and 3 which specify that the doctype-statement is case-insensitive. Also note the number of spaces inside the statement can vary.

And note the clause "A DOCTYPE is a required preamble."