Older versions of Android — Android 4.4 KitKat and older — have an integrated way to bypass your pattern, PIN, or other password if you forget it. To find this feature, first enter an incorrect pattern or PIN five times at the lock screen. You'll see a "Forgot pattern," "forgot PIN," or "forgot password" button appear. Tap it. You'll be prompted to enter the username and password of the Google account associated with your Android device.
Modern Android devices(Android 5.0 and newer) work a lot more like Apple's iPhones and iPads. If you forget the code, you'll need to reset it to its factory default settings to regain access. This begins to make sense when you consider Google's desire to encrypt all Android devices out of the box automatically. The PIN or password is used as part of the key to decrypt the data stored on an encrypted Android device.
