This will show you how to change PIN code settings for SIM Card in MIUI 7.
Instructions for other MIUI versions
Change SIM Card PIN settings in MIUI 8
Change SIM Card PIN settings in MIUI 9
In System Settings tap
Securitysection tap on SIM Card name which PIN settings you want to change.
If you haven’t changed your SIM Card name it will simply be name of your mobile provider. In this case it is: verizon
Lock SIM cardyou can choose if phone should ask for PIN to unlock the SIM Card after each reset and
Change SIM PINoption to change or set new PIN code.