I've seen so many videos on different topics regarding GHL services, but what I still fail to understand is how the customer will use the service. For example missed call text back, once I set it up, will the client have to download GHL on their phone and text their customers through that? Will they have to set everything up on their app themselves, can someone please help me understand the customer side of things and how that works, also in terms of what I'm supposed to do for them. Thanks