Installing R
There are two important ways to install R.
Contents
Base Interpreter
Most Linux and BSD distributions will offer an r package.
For Windows, see the project website.
RStudio
RStudio is a partially-proprietary IDE for R with near universal adoption. (The product is maintained in open source by Posit, while various premium features require a paid license under certain circumstances. See Shiny for example.)
RStudio is not generally packaged. See the product website.