A very basic scatterplot built with base R and the plot() function. Explanation and code provided.
The plot() function of R allows to build a scatterplot. Both numeric variables of the input dataframe must be specified in the x and y argument.

# Create data
data = data.frame(
  x=seq(1:100) + 0.1*seq(1:100)*sample(c(1:10) , 100 , replace=T),
  y=seq(1:100) + 0.2*seq(1:100)*sample(c(1:10) , 100 , replace=T)
)
# Basic scatterplot
plot(x=data$x, y=data$y)Here is a description of the most common customization:
cex: circle sizexlim and ylim: limits of the X and Y axispch: shape of markers. See all here.xlab and ylab: X and Y axis labelscol: marker colormain: chart title
# Create data
data = data.frame(
  x=seq(1:100) + 0.1*seq(1:100)*sample(c(1:10) , 100 , replace=T),
  y=seq(1:100) + 0.2*seq(1:100)*sample(c(1:10) , 100 , replace=T)
)
# Basic scatterplot
plot(data$x, data$y,
     xlim=c(0,250) , ylim=c(0,250), 
     pch=18, 
     cex=2, 
     col="#69b3a2",
     xlab="value of X", ylab="value of Y",
     main="A simple scatterplot"
     )ss

# the iris dataset is provided by R natively
# Create a color palette
library(paletteer)
colors <- paletteer_c(package = "ggthemes", palette = "Green-Blue-White", n = 3)
# Scatterplot with categoric color scale
plot(
  x = iris$Petal.Length, 
  y = iris$Petal.Width,
  bg = colors[ unclass(iris$Species) ],
  cex = 3,
  pch=21
)ss

# the iris dataset is provided by R natively
# Create a color palette
library(paletteer)
nColor <- 20
colors <- paletteer_c(package = "viridis", palette = "inferno", n = nColor)
# Transform the numeric variable in bins
rank <- as.factor( as.numeric( cut(iris$Petal.Width, nColor)))
# Scatterplot with color gradient
plot(
  x = iris$Petal.Length, 
  y = iris$Petal.Width,
  bg = colors[ rank ],
  cex = 3,
  pch=21
)