How does Apple 6s intercept phone calls and text messages that are not in the address book?

The specific operation of Iphone to blacklist incoming calls is as follows:

Method 1: directly add the phone number to the blacklist.

1. Go to the Phone icon on the Iphone home screen.

2. Take the phone number in "Recent Calls" as an example: Click "Recent Calls" and then click the "exclamation mark" icon to the right of the phone number to be blacklisted.