Forgot password

See information in https://support.apple.com/en-us/HT202860

What do you exactly mean? Do you mean you've forgotten the Apple ID password or screen passcode?

If you forgot the Apple ID password, you can try to reset your password: If you forgot your Apple ID password - Apple Support

If you forgot your screen passcode, you can take your device together with its receipt to the nearby Apple Store to ask for the help of Apple technician.