Apple iPhone 4 support.

To set a passcode lock:

1. On the homescreen, tap Settings





2. Tap General





3. Tap Passcode Lock





4. Before you set up a passcode, you can choose to set a four digit code by leaving the Simple Passcode option On. If you change this option to Off you can enter a longer code. To set up a passcode, tap Turn Passcode On





5. You'll be asked to create a passcode lock and enter it twice. If you've chosen to use a longer code, you'll need to tap Next before you can re-enter the code







6. You can choice how long it takes for your iPhone to lock automatically by tapping Require Passcode and selecting your chosen timeframe

Your iPhone will now lock when you're not using it.