Secure AirDrop
What is AirDrop?
AirDrop 
is an easy way to share images, documents, or other files between Apple devices that are near each other. You can enable your device to share with everyone near you, limit sharing to only your contacts, or share with no one.
Note: The Contacts Only option is available on devices with iOS 10, iPadOS 13.1, and macOS 10.12, or later. If your device uses an earlier software version and you want to limit who can send files to you over AirDrop, you can turn it on when you need it and then disable it when not in use.
Find out how: To view a task below, select the plus button 
next to its title.
> General, tap AirDrop, then choose an option that works best for you.
in the Dock to open a Finder window.
in the menu bar, then click 
next to AirDrop, then choose an option that works best for you.