my son forgot his password for his iphone 8 how can we get into his phone

Hi there,

Try the following steps: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled

If it is his Apple ID, follow these steps: If you forgot your Apple ID password

Follow this link

If you forgot your Apple ID password 

If you have issues when you try to sign in with your Apple ID password, use these steps to reset it and regain access to your account.

https://support.apple.com/en-us/HT201487