AuxiliarySoftware: Install R Commander Auxiliary Software
In Rcmdr: R Commander

Install Pandoc and LaTeX to increase the capabilities of the R Commander.

The capabilities of the R Commander can be enhanced by installing additional software. The R Commander will work without this software but some features will not be activated. The following addiitional software can conveniently be installed via the R Commander Tools > Install auxiliary software menu. The resulting dialog box will take you to websites where the software can be downloaded. This menu item will only be displayed if one or more of these software packages are missing.

Here are the details:

Pandoc: The Pandoc documentation-conversion software is used by the R Commander to generate HTML (web), PDF, and Word files from the editable R Markdown document that is created by default during an R Commander interactive session. Pandoc is required by the rmarkdown package, which, along with the knitr package, performs these conversions. In the absence of Pandoc, R Markdown documents in the R Commander are processed by the older markdown package, which is capable only of producing HTML output. Pandoc is available from http://johnmacfarlane.net/pandoc/installing.html.

On Windows systems, Pandoc installs into a non-standard location in your user directory, typically C:\Users\<your user id>\AppData\Local\Pandoc\, and then places this subdirectory on your system path. You may have to reboot for the change to your path to take effect, and I have found it necessary on two Windows 10 systems to re-run the Pandoc installer, first to uninstall Pandoc, and then to re-install it before it would be work.
LaTeX: The LaTeX technical-typesetting system is required by the R Commander for PDF output from R Markdown or knitr documents produced during interactive R Commander sessions. In the absence of LaTeX, direct PDF output is unavailable. Complete LaTeX systems are available for the various platforms that support R and the R Commander, including MikTeX from http://miktex.org/download for Windows systems; MacTeX from http://www.tug.org/mactex/ for MacOSX; and various sources (see http://latex-project.org/ftp.html) for Linux/Unix systems.