Airdrop is missing from Finder
MacBook Pro, OS X El Capitan (10.11.6)
MacBook Pro, OS X El Capitan (10.11.6)
AirDrop system requirements
To send items to an iPhone, iPad, or iPod touch, or to receive items from those devices, you need a 2012 or later Mac model with OS X Yosemite or later, excluding the Mac Pro (Mid 2012).
To send items to another Mac, you need:
There has been similar issues after upgrading to El Capitan from Yosemite.
Maybe this will help: If Share options or Markup is missing after upgrading to OS X Yosemite or El Capitan - Apple Support
Airdrop is missing from Finder