Unfortunately, this isn't free for commercial use, so perhaps something like Google Charts is more suitable (depending on your use case). There are plenty of alternatives out there.
Highcharts is neat because it's a high-level api around charting. If you want to make charts, it's one of the most customizable and well-documented API's out there. If you want to build a custom visualization, highcharts offers a good amount of customizability, but sometimes you just gotta drop down into assembly.