How to format the name of an R package in thesis?
You can do this by adding the following to your preamble. Something like this:

\newcommand{\pkg}[1]{{\normalfont\fontseries{b}\selectfont #1}}
\let\proglang=\textsf \let\code=\texttt
\begin{document}
Then you can refer to R as \proglang{R}, to a package
\pkg{packagename}, and to a function as \code{functionname}.
\end{document}