The built in Google Home integration doesn't support fans. The interface gives you absolutely no feedback that a particular devices isn't capable of being added to Google Home.
Even if you go thru the rather complicated route of installing the community version, it will allow you to create and add fan devices to Google Home, but depending on how your fan is controlled it can be rather limited.. in my case the fan controls appear in Hubitat as command actuator "button devices", and button devices don't translate to Google Home very well at all.
Your mileage may vary.
