A "Hello, World!" program is generally a simple computer program which outputs (or displays) to the screen (often the console) a message similar to "Hello, World!" while ignoring any user input. A small piece of code in most general-purpose programming languages, this program is used to illustrate a language's basic syntax. A "Hello, World!" program is often the first written by a student of a new programming language, but such a program can also be used as a sanity check to ensure that the computer software intended to compile or run source code is correctly installed, and that its operator understands how to use it.
The HyperText Markup Language, or HTML is the standard markup language for documents designed to be displayed in a web browser.
It can be assisted by technologies such as
Created along with the beginner-friendly learning resource "Getting started with the Web" from the MDN Web Docs (previously Mozilla Developer Network and formerly Mozilla Developer Center).
Definitions: Wikipedia