How can invent my own game

Question

UNKNOWN

Answer 1

1: Learn a programming language.
2: Find a way to make graphical programs with the programming language.

With pure HTML you might not create any games, but if you also learned JS, then you can create games using canvas or SVG.

Answer 2

I recommend using Unity, as it is very useful in creating video games but it's recommended to learn C# first before using Unity to code your game.