Iphone 12 side button disable
I am being asked to double tap side button to confirm App purchase. This doesn't work - just turns my ph off!!! Searches say to go via Accessibility to disable and choose to toggle on 'use password' - it doesn't have that option. Can someone please tell me (in basic steps please :-)) how to go back to the original put your Apple ID password in to confirm a purchase from the App Store? Many thanks in advance.
iPhone 12, iOS 14