Getting iphone 7 back online after disabled

Hi, I was having issues with my son's phone use. He uses a password I don't know. We took phone away for personal reasons and I tried to guess is password. Now it is disabled and says connect to itunes, but that does nothing. It is an iphone 7. I don't know what to do. Even if I give it to my son there is no way to get to his password log in.