Who came up with words and their meanings?

I mean if I just make up a word then say it means 'this' and enough people use it, is it then classed as a word or not?

How to people create more words in that case? Is it possible to create more words?

Should we create some words with some meanings that we have to use and try to get it recognised as a word?

LET'S CREATE SOME NEW WORDS!