i forget screenlock 4digi iphone 4

If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

I ALREADY OPEN MY APPLE BUT I FORGET THE APPLE i THAT I HAVE BEEN USED

Sorry? Maybe you should try that again in your native language. That makes very little sense.

I forgot my password to open the phone

I already signed in my apple id but the phone is still locked

It would be, logging into your account won't unlock your phone - you need to follow these instructions : If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support