如何在ggplot2中制作更美观的字幕？

I tried to add captions in some plots that will be shown in a .rmd file, but the captions added are not very aesthetically pleasing. It will look much better if I just include the captions in the .rmd file instead of the plot. Are there any ways to make the captions look prettier in ggplot2?I tried to add captions in some plots that will