function par()

‘par’ can be used to set or query graphical parameters.
Parameters can be set by specifying them as arguments to ‘par’ in ‘tag = value’ form, or by passing them as a list of tagged values.

par(…, no.readonly = FALSE)

Parameters are queried by giving one or more character vectors of parameter names to ‘par’.

mar
A numerical vector of the form ‘c(bottom, left, top, right)’ which gives the number of lines of margin to be specified on the four sides of the plot. The default is ‘c(5, 4, 4, 2) + 0.1’.