The Shiny app package is basically a tool where you, with your R knowledge, build a web page and present the result of your R scripts to everybody, including people who don't know R. They can access the information without doing anything but clicking on a website. You, otherwise, need to know the scripts from the analysis you wish to make available.

The way that the shiny package works can be split into two parts: the user's interface and the server function. The user's interface is the website or R Markdown document that users interact with and spend some clicks on. The server can be your computer or a web server where the website is hosted—it must be a server running the R language. When the users request a new visualization, the Shiny app serves the web server with a new R script, then it runs the R codes and serves the new display to the Shiny app. If you configure your R app to be in the cloud, the user will be able to request others' information without your solicitude, but it requires a web page server with the cloud service available.