Airdrop is Apple’s method of sharing content between iOS mobile devices. If your iPhone or iPad Airdrop settings are set to “everyone” your device will show in nearby iOS users’ Airdrop list. They can send you content, photos, files, and such from their device. The files won’t automatically be transferred to your device; you have to accept the incoming transmission. In some cases the file preview, popping up on your device’s screen, may be… unexpected.
To prevent random Airdrop file transfer requests, swipe up from the bottom of your device, touch Airdrop in the Control Center screen, and select Contacts Only. By doing this, only trusted sources can send you content.
Also published on Medium.