Make sure both iPhones have Wi-Fi and Bluetooth turned on
Make sure both iPhones are close to each other
Open Control Center on both iPhones
Turn on AirDrop on both iPhones
Choose Contacts Only or Everyone for AirDrop visibility
Open the photo, file, or item you want to send on the sending iPhone
Tap the Share button
Tap AirDrop
Select the receiving iPhone
On the receiving iPhone, tap Accept
Wait for the transfer to finish
Open the received item in the appropriate app if needed