Change size of legend in ggplot2

Question

This code:

ggplot(mapping = aes(x = x, y = y)) +
  geom_line(data = error_Legendre, aes(colour = "Legendre")) +
  geom_line(data = error_LLm10, aes(colour = "LL")) +
  xlab('x') +
  ylab('y')+
  scale_colour_manual(
    values = c("blue", "red")
  )+theme(axis.text=element_text(size=20))

changes correctly the axis text. I would like to change the size of the legend, i.e. Legendre and LL.

Answer 1

add this in your theme : +theme(axis.text=element_text(size=20), legend.text = element_text(size=10)) but do know there are several options for core text, titles, etc. This page lists the options : https://www.statology.org/ggplot2-legend-size/