Q: Unlock iPhone

Push the home button and enter the four digit (or longer) code.

IIt did not work it says my passcode has zero values

You will need to contact your wireless carrier and first see if they are willing to unlock your device. If they are, they will usually send you an email which will contain the passcode to unlock the device.

I forgot my code to unlock my iphone

See here: https://support.apple.com/en-us/HT204306