For iOS 11 and later, it is more obvious. You will need to select Siri & Search on the main screen of the Settings app. Then move the "Press Home for Siri" slider to off (toward the left) and then press "Turn Off Siri" on the pop up.
For iOS 11 and later, it is more obvious. You will need to select Siri & Search on the main screen of the Settings app. Then move the "Press Home for Siri" slider to off (toward the left) and then press "Turn Off Siri" on the pop up.