Checkout for WooCommerce uses the system font stack by default.
Using Google Fonts
To change your fonts, go to Settings > CheckoutWC > Design and change the the Body Font and Heading Font settings:
Then save your settings and you’re good to go.
If your font list isn’t loading.
Occasionally, our fetch to Google may return an error which gets cached as a transient. To fix this, try deleting all of your transients.
With WP CLI you can use this:
wp transient delete –all
If you don’t have access to WP CLI, you can use a plugin like this:
Using custom fonts.
If you can’t find the font you need with Google Fonts, you can add a custom font. This will require custom coding.
You can insert your style tags into Settings > CheckoutWC > General > Header Scripts.
We can’t really help with this part, but if you run into a snag you’re welcome to contact support and we’ll try to point you in the right direction.