Does the iPhone 8 have "call blocking and identification" in the phone settings? I don't see it on my phone

Go to Settings > Phone. Tap Call Blocking & Identification. Under Allow These Apps To Block Calls And Provide Caller ID, turn the app on or off.

Detect and block spam phone calls - Apple Support

You can any number to the blocked list, but spam calls usually come from a different number each time. That’s why Apple added Silence Unknown Callers.

Many carriers offer blocking apps, so check with your carrier. For example, AT&T has Call Protect, which is free. And there’s a good app from Nomorobo that costs $2 a month but works well.