i forgot my iphone passcode

No Problem, in addition to the article viewed above that requires a computer to reset the passcode, you also have this option to wipe your device and reset your passcode using your Apple ID. There is no way to get around erasing your device to reset a forgotten passcode.

If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support

See if this helps: If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support