What most people call drones is actually multicopter configuration of UAV. There are also drones with wings, helicopter configuration and the latest trend: hybrid configuration that has wing and tri or quad arrangement of engines for vertical take-off and landing.
Airplane configuration drone
Hybrid drone – VTOL flying wing
Helicopter drone-typical rc helicopter with autopilot
Every configuration has it’s pros and cons. Best overall performance has hybrid configuration. It has flight range slightly less than plane configuration and possibility to take off and land in vary small areas but it needs larger space for transportation than typical quad drone. Helicopter drone has ability of autorotation, it means if one engine fails, it can land due to large inertia od moving rotor blades. In contrast in multirotor drones, autorotation is not possible cause propellers are short and much lighter than helicopter blades.