Even in the era of the Internet, PDF documents are a really convenient way to share your results.
That is probably why RStudio provides you with an easy way to create PDF documents from your R Markdown documents.
To produce PDF documents from our device, we first need to install the latest distribution of a convenient LaTeX engine.
On Apple devices, we suggest downloading the latest Mactex version from http://tug.org/mactex/mactex-download.html, while Windows users can download Miktext from http://miktex.org/download.
Linux users can use Texlive, which can be found at https://www.tug.org/texlive/quickinstall.html.