The Electoral College is how the U.S. decides its president. When people vote in an election, they are actually voting for their state's choice for president. Each state has a certain number of votes called "electoral votes”. Most states give all their electoral votes to the candidate who gets the most votes from the people in that state. To win the presidency, a candidate needs to get more than half of the total electoral college votes across the country, which is 270 out of 538.
The popular vote is the total number of votes cast by the people in an election. In a presidential election, it refers to the direct votes each candidate gets from voters across the entire country.