Annotate ggplot with text labels using built-in functions and create non-overlapping labels with the ggrepel package.

I want to know how to proper add p value using non-scientific format to a ggplot2 figure? Whether or not depend on method mentioned above is OK. Thank you!

This is a follow-up post to the one I made yesterday and a continuation from #261. I have a ggplot that has no theme (void) that allows for the plot to align with the heatmap within the annotation.