1. For better security, you can set a passcode that must be entered each time you turn on or wake up iPhone.
   Note: To set a passcode: Go to Settings > Touch ID & Passcode (iPhone models with Touch ID), then set a 6-digit passcode or Settings > Passcode (other models), then set a 4-digit passcode.
   
2. To Set your passcode, go to Settings > Passcode.
   
3. To increase security, turn off Simple Passcode and use a longer passcode. To enter a passcode that’s a combination of numbers and letters, you use the keyboard. If you prefer to unlock iPhone using the numeric keypad, set up a longer passcode using numbers only.
   Note: Learn more from Apple support article: If you forgot the passcode for your iPhone or your device is disabled
   
4. Allow access to features when iPhone is locked. Go to Settings > Passcode.
   Note: Optional features include: Today, Notifications View, Siri, Reply with Message, Wallet.
   
5. Allow access to Control Center when iPhone is locked. Go to Settings > Control Center
   
6. Erase data after ten failed passcode attempts. Go to Settings > Passcode, then tap Erase Data. After ten failed passcode attempts, all settings are reset, and all your information and media are erased by removing the encryption key to the data.
   Note: To learn more about requesting a device unlock for your AT&T mobile device, visit att.com/deviceunlock. If your device is locked and is requesting a "PUK" code, click here for instructions on how to obtain your PUK or PUK2 code to unlock your SIM card.