Offline or Online plot in Shiny APP

I cannot understand the offline and online plot rule by plotly in shiny APP.

I have installed the plolty package on my host server. If I use plolty in a shiny APP and visit this shiny APP from a guest IP address (remote visiting via TCP/IP), how does plotly work? Dose the figure plot on the host server using the local package and send it to the guest’s browser?

I can get the figure in this case but I don’t how this work.

Thank you very much