T change the fold of your theme you need to go to Appearance -> Theme Options -> Typography see the image below.
You can load two google fonts for your site. The first one is for headings and the 2nd one is for the body font. To load a google font you need to visit www.google.com/fonts and find the font you want to use on your site. After that you need will have to get the font link code and font family code that you will have to put on your theme option. To understand the full process please see the video below.