Enable Silence Unknown Callers
If you’re like the rest of us, you probably hate spam and robocalls. Luckily, Apple has added a new feature that could help reduce the number of random calls you receive each day. Enter Silence Unknown Callers.
Essentially, it sends any call from a number not in Contacts, Messages or Mail straight to voicemail. And while it may not be for everyone, many users can probably take advantage of the feature. You can enable it in Settings > Phone > Silence Unknown Callers.