Open Settings
Tap General
Tap Software Update
If the update is downloading, tap Pause Download or Stop Download if available
If the update is already downloaded, tap Delete Update
Turn off Automatic Updates
Go to Settings
Tap General
Tap Software Update
Tap Automatic Updates
Turn off Download iOS Updates
Turn off Install iOS Updates
Turn on Low Power Mode
Disable Wi-Fi if you want to prevent the update from continuing
Restart the iPhone if the update is stuck
If the update is installing, wait for it to finish before making changes
If needed, remove the downloaded update from iPhone Storage in Settings
Avoid connecting to Wi-Fi until you are ready to update