Located in Appearance >> Customize >> Font Selector.

Here’s what it looks like in back-end:

wordpress-theme-dw-jason-font-selector
Font Selector in Back-end

First, you need to go to Google Font Library to find web font you like. After finding, head over “quick-use” button.

Quick-Use button
Click on Quick-Use button

Once you clicked quick-use button,you will choose styles as you want.

wordpress-theme-choose-style-as-you-want
Choose Styles as you want

Next, scroll down till you see the pane titled “Add this code to your website” as followings:

Add code to your website

You can see that there are 3 tabs ” Standard”, “@import”, “Javascript”, however, you only use the first tab “Standard” for your site.
Just copy the code above, then go to Appearance >> Customize >> Font Selector, paste the code into the Heading Font – Link section:

Paste code into Heading font - Link
Paste code into Heading font – Link

Once done that, the next thing you need to do is to integrate the fonts into your CSS. Navigate to Google Font Library, scroll down, copy the code like this:

wordpress-themes-dw-jason-integrate-the-font-to-css
Integrate the fonts into your CSS

Then back to Customize >> Font Selector, paste the code you copied above into Heading Font – Font Family:

wordpress-theme-dw-jason-add-code-to-font-family
Add code to Font Family

Font-weight allows you to define how thick and thin characters in text should be presented in front-end.

The font-weight will be based on styles you chose above.

wordpress-themes-choose-font-weight
Styles you chose

In the screenshot above, 400 is the same as normal and 700 is the same as bold.

wordpress-theme-font-weight
Font Weight

To have Body Font, just follow the steps above for Heading font.