Could someone explain the process of how a death certificate gets made out?

Could someone explain the process of how a death certificate gets made out when a person dies at their home after paramedics are unable to resuscitate the person and the body gets transferred to the hospital by paramedics? How can cause of death be determined for sure if there is no autopsy performed, but the paramedics are fairly sure what the person died from based on their exam of the body while trying to revive the person? And how does the death certificate get into the hands of the deceased person's physician to sign the death certificate (especially if the person died on a weekend when doctor's offices are typically closed)?