The espresso shot is as simple as it gets.
The americano is a shot of espresso with water.
The latte is an espresso shot with steamed milk and a small amount of foam.
The cappuccino is similar to the latte, but with more foam and less steamed milk. It is considered the "lighter" option.
The mocha is espresso with chocolate, milk, and whipped cream. This is a popular option for those who don't particularly enjoy the taste of coffee or are just starting to try new coffee drinks.