This article explains how to turn off AirDrop on iPhone, iPad, and Mac.
How do I turn off Airdrop on an iPhone?
The process for turning off AirDrop on iPhone and iPad is the same, but there are two different ways to do it: through Control Center or Settings. Using Control Center is faster.
Swipe down from the top-right corner of the screen to open the Control Center.
Tap and hold the Network settings tile (top left with Airplane mode, Bluetooth, and more). The tile will expand to reveal more options.