This article explains how to convert a Google Doc to PDF. The Google Docs website provides a few ways to do this depending on what you want to do with the PDF after it's been converted.

Converting documents to PDF from any web browser is not a problem as long as you are using Google Docs. We explain how in this article.

At the top of your Drive window, you’ll see an option to Open With Google Docs. If you select this, Google will convert the PDF to a Docs file and open it for you.