All unmanned aircraft in the US over 0.55 lbs, regardless of for commercial or recreational use, MUST be registered with the FAA. You can register your drone HERE. Once you register your drone, you have to either "affix" it to your drone (aka - stick it on there somewhere) or it must be stored somewhere that is accessible WITHOUT a tool. Remember this for the exam!
The Remote Pilot in Command (RPIC) is the person who is ultimately responsible for the safe operation of the unmanned aircraft. They must hold a valid and current Remote Pilot certificate. It is required that one RPIC be designated before each flight. The RPIC has the final say for all flight operations, whether to fly or not depending on the condition of the weather, the unmanned aircraft itself, and the overall flight environment and circumstances.
Other individuals without a Remote Pilot certificate may also fly the unmanned aircraft for commercial purposes, but in these instances the person manipulating the controls must be supervised by the RPIC and the RPIC must be able to take back control at any moment.
The RPIC must also conduct a pre-flight inspection to ensure that the aircraft is suitable for safe operation.