Google fonts is an extremely useful resource for web developers. It offers 843 font families that can easily be used on a web page. Making styling and theming a website such a hassle-free task.
To use Google fonts navigate to Google fonts and choose your font/s. You need to embed the link to your chosen font in the <head> tag like for Roboto:
<head> <link href="css/yourcssfile.css" rel="stylesheet"> <link href="https://fonts.googleapis.com/css?family=Roboto" rel="stylesheet"> </head>
Then in your CSS you need to specify the font family in the rule you want it used for, say we want to use it for h1,h2 and h3:
h1,h2,h3 { font-family: 'Roboto', sans-serif; }
Thats how easy it is. Do be careful though as using several fonts will start to impact your webspeed.