The easiest to use Google Fonts plugin.
Fonts Plugin is a freemium WordPress plugin that allows you to add any of Google's 900+ fonts to your website in minutes.
Using the live preview you can choose different fonts for your site logo, content, headings and more.
Once you are happy with your font choices, take it a step further and configure the typography settings: font size, weight, color, line-height.
The plugin loads your fonts in the most optimal way, ensuring your website loads just as fast (or even faster) than if you hard-coded them.