Look for the charging icon on the battery indicator in the status bar
Check for the lightning bolt icon next to the battery symbol
See if the battery icon turns green or shows a charging symbol on the Lock Screen
Check the battery percentage to see if it increases over time
Plug in the iPhone and feel for a brief vibration or sound if enabled
Open Control Center or the Lock Screen to confirm the charging indicator
Use a MagSafe or wireless charger and check for the charging animation
Look for the low-battery screen changing to the charging screen when connected