The Founding Fathers created the Electoral College after much debate and compromise, but it has provided stability to the process of picking presidents. Though the winner of the national popular vote typically takes the presidency, that vote failed to determine the winner in five elections: 1824, 1876, 1888, 2000 and 2016 when Hillary Clinton gained 2.8 million more votes.
President Trump won 306 electorcal college votes to Hillary Clinton's 232 on Nov 8, 2016. Trump campaigned to win the electoral votes, not the majority vote, by visiting the closely contested states. And in doing so Trump turned seven blue Democrat states to red Republican states. Trump supporters also argue Hillary received more votes than Trump because millions of illegal immigrants voted for her.
The Electoral College ensures that votes by Americans from all 50 states count. Without the Electoral College many of the smaller populated states (minority of the population) would be ignored and would not have a voice. Instead only the top few heavily populated states would be the voice, and therefore control, the entire rest of the country. Presidential candidates would only need to campaign in a handful of states, ignoring the majority rest of the states.
Understanding The Electoral College Map