By default, the SIM card comes with a pre-defined PIN. It's rare that you can remember it well, so it's useful to be able to change it on your Xiaomi smartphone.

Note: If the PIN has been entered incorrectly three times in a row, we need the eight-digit SIM-PUK to unlock the SIM card, which we can find in the SIM card documentation next to the PIN.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Passwords & security
Step 3:  Tap on  Privacy
Step 4:  Choose a  SIM card   (Dual SIM)
Step 5:  Tap on  Change SIM PIN
Step 6:  Enter the current  PIN  and tap  OK
Step 7:  Enter the new  PIN  and tap  OK
Step 8:  Enter the new  PIN  again and tap  OK
  1. Open the Settings
  2. Tap on Passwords & security
  3. Tap on Privacy
  4. Choose a SIM card (Dual SIM)
  5. Tap on Change SIM PIN
  6. Enter the current PIN and tap OK
  7. Enter the new PIN and tap OK
  8. Enter the new PIN again and tap OK

Xiaomi Instructions