There are two quite famous way to plot using the Pandas or the Matplotlib library.
Using the matplotlib library, you can set the title of the figure using the axes.set_title() method.
Using the DataFrame.plot() method you can set the title of the figure by passing the title="my title" parameter.
Here you are, you now know how to add a title to a barplot in Python.
More on plots
If you want to know more about how to add labels, plot different types of plots, etc... checkout the other articles I wrote on the topic, just here :