Turn SIM PIN On / Off - HTC One® (M8) for Windows®
Enabling the Subscriber Identity Module (SIM) Personal Identification Number (PIN) locks the SIM card so it can't be used until the correct code is entered. If the incorrect PIN code is entered too many times, refer to Locating the 4G SIM PIN/PUK - My Verizon Website to obtain a new PIN Unblocking Key (PUK).
From the Start screen, swipe left to display the Apps list. Alternatively, tap All apps (located in the lower-right; may require scrolling to the bottom of the Start screen).
Tap the Moreicon (located in the lower right).
From the SIM security section, tap the switch to turn on (enable) or off (disable).
Enter the current SIM PIN then tap enter (located to the right, above the numeric keypad). The default SIM PIN is 1111.