March 3, 20120 is known as Super Tuesday because it’s the date 14 states hold their primary elections, including California. Because of the high number of states and delegates up for grabs, whoever becomes the nominee of the Democrat Party to be President of the United States may be determined by the Super Tuesday votes. And remember in addition to President, there are many other offices and measures being voted on, including our representatives for Congress (known as the United States Representative), Los Angeles County District Attorney, many Judges of the Superior Court, and various county measures.
California used to hold its primary in June, but because so many other states held their primaries earlier and the nominees were sometimes already decided, California moved its primary up to early March to become more relevant.
In addition to moving its primary up to March 3, 2020, California and Los Angeles County have instituted early voting procedures where voters could vote in certain places since February 22, 2020 and other places since February 29, 2020.