Charge the iPhone for at least 30 minutes
Check the charging cable, adapter, and power source
Force restart the iPhone
If the iPhone is connected to a computer, disconnect and reconnect it
Try a different charging cable and adapter
Clean the charging port gently
Check for signs of physical damage or liquid damage
Connect the iPhone to a computer and open Finder or iTunes
Put the iPhone into recovery mode and update or restore it
Try DFU mode restore if recovery mode does not work
Remove any accessories or cases
Let the iPhone cool down if it is overheating
Contact Apple Support or visit an Apple Store if the screen stays black