Why was george washington elected as the first president?

To be honest i read an article and it said that nobody knows how but as i read on it said that he help framed to constitution which made others feel as if he was a good leader and was a commander of the revolutionary war.

Washington served as a general and commander-in-chief of the colonial armies during the American Revolution, and later became the first president of the United States, serving from 1789 to 1797. He died on December 14, 1799, in Mount Vernon, Virginia