Customizing fonts can be a great and simple way to customize the look of your website to reflect your branding.
If you know your existing font-families you can add them (assuming they're web-safe fonts or included in Google Fonts).
If you don't know what fonts you'd like to use Google Fonts includes over 800 options.
You can easily adjust your primary fonts in Locable (see below):
Login to your account
Open Website & Embeds in the menu
Click Theme & Design
Click the green Manage Fonts button
Paste the font name that you'd like to use - you can also adjust font sizes and colors
If you don't know what font to use click Browse Google Fonts then copy the name in
And you're done!