Samsung Galaxy S4 User Manual page 391

Setting up SIM Card Lock
Prevent another user from using your SIM card to make unauthorized
calls or from accessing information stored on your SIM card by
protecting the information using a PIN code.
When enabled, your phone will ask for a PIN number each time you
use the phone. Using this option you can also change your SIM PIN
number.
1. From the main Settings page, tap More tab
2. Tap Set up SIM card lock.
3. Tap Lock SIM card, enter your SIM PIN code, then tap OK.
Note: You must activate Lock SIM card before you can change your
SIM PIN code.
To change an existing SIM Card PIN:
1. Tap Change SIM PIN.
2. Enter the old SIM PIN code and tap OK.
3. Enter the new SIM PIN code and tap OK.
4. Re-type the new SIM PIN code and tap OK.
Password Settings
When you create a phone password you can also configure the
phone to display the password as you type it instead of using an
asterisk (*).
1. From the main Settings page, tap More tab
2. Tap Make passwords visible to activate this feature.
Changing Your Settings
Security.
Security.
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