R: How can I annotate a ggplot with a text box?

Question

I am looking to add a small white text box, with custom text in the body of my ggplot plot. The text I want to add is to identify a horizontal line I am adding to the plot.

Answer 1

You can simply change to

annotate("label", x = max(grossunits), y = meancbrate, label = "avg rate") 

which will use geom_label rather than geom_text and so you get a rectangle around the label.