I think you are a little bit confused, RStudio is an IDE (Integrated Development Environment) it doesn't come with any built-in mapping capability, however, there are a lot of options for mapping in R (which one to use depends on your personal preferences and the kind of map you are looking for), as an example here is simple map of Germany and Poland.
library(tidyverse)
library(rnaturalearth)
germany_poland <- ne_states(country = c("germany", "poland"), returnclass = "sf") %>%
select(name)
ggplot(germany_poland) +
geom_sf() +
geom_sf_text(aes(label = name), size = 2, color = "blue") +
labs(title = "Germany and Poland") +
theme_minimal() +
theme(plot.title = element_text(hjust = 0.5, size = 20),
axis.title = element_blank(),
plot.background = element_blank(),
plot.margin = margin(5, 0, 5, 0))

Created on 2019-09-24 by the reprex package (v0.3.0.9000)