Pygame doesn't have built in functionality to allow you to display text on the screen. In order to display text, you have to work through a few steps of converting the text into an image and then showing the image on the screen.
In this video I will explain how this process works and I will create a helper function that allows us to easily display text on the screen. This helper function can then be easily called whenever needed from the main game loop.
Take a look at the tutorial on my website for a reference on working with text here: http://www.codingwithruss.com/pygame/working-with-text-in-pygame/