How does the Highcharts License work?

I'm developing an intranet for a company that is my client. For now it is just a prototype, only in the future will be marketed. On this intranet there are interactive graphics whose codes come from the Highcharts demo pages ( How are you here ). For clarity, I did not install the software. In that case, how does the license work? Do I need any? If so, which one? Thanks for any clarification.