We had this in the beta version of the editor but the new version is more advanced and has more options so that you can customize your poster any way you want. You can used it to easily create demotivational posters in just a few steps.
You’ll find the plugin in the Tools – Extensions menu, make sure to have it enabled. The customizing window will help you set up a style for your text. You can change the font size and also choose from a variety of fonts the one you like best. Have fun exploring your creativity!