The serial number of your DJI drone might be needed if you buy DJI Care Refresh or are working with DJI support. Here’s where you can find the serial number on any DJI consumer drone model:
DJI Mavic models
(Mavic Pro, Mavic Pro Platinum, Mavic 2, Mavic Air):
DJI Spark
DJI Phantom 4 models
(Phantom 4, Phantom 4 Advanced, Phantom 4 Pro, Phantom 4 Pro V2)
DJI Phantom 3 models
(Phantom 3 Professional, Phantom 3 Advanced, Phantom 3 Standard, Phantom 3 4K, Phantom 3 SE)
See this page for the serial number location for other DJI products not listed above.