By default, when someone calls your Grasshopper phone number the Caller ID on your phone will show that your Grasshopper number is calling. This way, you'll always know that it's a business call being forwarded from your Grasshopper phone number. You can choose to change this setting for each of the forwarding numbers used by your extensions. 

TIP: Save your Grasshopper number as a contact in your phone to make it even easier to see when it's a Grasshopper call. This is especially helpful if you have multiple Grasshopper numbers! By default, the caller ID on your phone will show your Grasshopper number as the number calling, so you’ll always know it’s a business call. You can also change how calls are announced