Shiny Tutorial Lesson 5: How to add counties name on the map

...Hello,
On the basis of R codes in Shiny Tutorial Lesson 5, I am using the following R codes to create a map in Shiny. I am interested in Ohio's counties and therefore I filtered data using subset command. I have two questions:
1- How can I add the name of counties on the map?
2- How can I increase the size of the map.
Thanks,

library(shiny)
library(dplyr)

if(!require(maps)) stop("This app requires the maps package.\nPlease install it and then try again.")
if(!require(mapproj)) stop("This app requires the maps package.\nPlease install it and then try again.")

counties <- subset(counties, region== "ohio")

mp <- map("county", plot=FALSE, namesonly=TRUE)
c.order <- match(mp,
paste(counties\$region, counties\$subregion, sep = ","))

shinyServer(function(input, output) {

indexInput <- reactive({
var <- switch(input\$var,
"Total Population (logged)" = log(counties\$pop),
"Percent White" = counties\$white,
"Percent Black" = counties\$black,
"Percent Hispanic" = counties\$hispanic,
"Percent Asian" = counties\$asian)

``````var <- pmax(var, input\$range[1])
var <- pmin(var, input\$range[2])
as.integer(cut(var, 100, include.lowest = TRUE,
ordered = TRUE))[c.order]
``````

})

switch(input\$var,
"Percent White" = colorRampPalette(c("white", "darkgreen"))(100),
"Percent Black" = colorRampPalette(c("white", "black"))(100),
"Percent Hispanic" = colorRampPalette(c("white", "darkorange3"))(100),
"Percent Asian" = colorRampPalette(c("white", "darkviolet"))(100))
})

legendText <- reactive({
inc <- diff(range(input\$range)) / 4
c(paste0(input\$range[1], " % or less"),
paste0(input\$range[1] + inc, " %"),
paste0(input\$range[1] + 2 * inc, " %"),
paste0(input\$range[1] + 3 * inc, " %"),
paste0(input\$range[2], " % or more"))
})

output\$mapPlot <- renderPlot({

``````map("county", fill = TRUE, col = fills,
resolution = 100, lty = 0, projection="polyconic",
myborder = 0, mar = c(0,0,0,0))
map("state",col = "white", fill=FALSE, add=TRUE, lty=1,
lwd=1,projection="polyconic", myborder = 0,
mar = c(0,0,0,0))
legend("bottomleft", legend = legendText(),
fill = shadesInput()[c(1, 25, 50, 75, 100)],
title = input\$var)
})
``````

})

I think both of these questions are more about the `maps` package than R.

`map From maps v3.3.0`
Draw Geographical Maps
Draw lines and polygons as specified by a map database.

Country labels, I think you use `map.text`

A good way to get help would be to create a REPRoducible EXample (reprex)? A minimal reprex makes it much easier for others to understand your issue and figure out how to help.