By default, R Markdown displays data frames and matrixes as they would be in the R terminal (in a monospaced font). If you prefer that data be displayed with additional formatting you can use the knitr::kable function, as in the .Rmd file below. This file is available here on RStudio Cloud.

Note the use of the results='asis' chunk option. This is required to ensure that the raw table output isn’t processed further by knitr.