Registering your aircraft under FAA Part 107
In order to fly legally, all drones need to be registered with the FAA under Part 107. Registering your aircraft is a simple, and straightforward process.
Go to faadronezone.faa.gov and register for a new account under Part 107. Be sure NOT to click the Section 336 part, as that is for recreational drone flyers.
In the account, go to "Add a UAS" and then enter the aircraft information.
Check out an pay the $5 registration fee.
Print out the registration certificate and keep it with the aircraft.
The process is very simple, straightforward, and should only cost $5. Be careful, because there are numerous instances of scams on the internet of people offering to register an aircraft for hundreds of dollars.