Question

What is a doctype and explain

Answer 1

The <!DOCTYPE> declaration is not an HTML tag; it is an instruction to the web browser about what version of HTML the page is written in. In HTML 4.01, the <!DOCTYPE> declaration refers to a DTD, because HTML 4.01 was based on SGML. ... HTML5 is not based on SGML, and therefore does not require a reference to a DTD.

                                                                   -google

Answer 2

Document type declaration, or DOCTYPE, is an instruction that associates a particular SGML or XML document (for example, a webpage) with a document type definition (DTD)