https://www.pocket-lint.com/how-to-screen-calls-on-iphone/
Please read more at the above link
For a while now, iPhones have allowed third-party apps to tackle automatic caller identification and blocking. I rely on Hiya, which offers some basic features for free, like flagging suspect spam. Its full features are gated behind a paywall, unfortunately, and even then, they only work if you’re signed up with one of the big three US carriers (AT&T, T-Mobile, or Verizon). You may have to do some searching in the App Store to find an app that works with your carrier at a price you can afford.
The good news is that Apple has a limited ID service of its own, dubbed Business Connect ID, which is on by default and completely free. The main issue is that it’s restricted to companies verified by Apple, so it may miss some smaller businesses, and it certainly won’t pick out scammers and stalkers.