We can add any custom font to these websites. If the client wants a custom font, I would highly recommend they choose a google web ready font. These are already integrated into our websites and we can quickly select them to be used.
There are over 800 of them that you can see here:
https://fonts.google.com/
If the client wants a font that is not a google web ready font, they would need to purchase it and provide it to us and they need to be made aware that not all custom fonts will work on all devices. Custom fonts wont always show on tablets and mobile devices. This is why i recommend they use google web ready fonts, they work on all devices.