How does Apple's mobile phone stop overseas calls?

Apple's mobile phone is hacked to prevent overseas calls as follows:

Tool: iPhone 8

Operating system: iOS 14.4. 1.

1. Take Apple 8 as an example. First, turn on the dial on the mobile phone, as shown in the figure below:

2. Select the nearest call after dialing is turned on, as shown in the figure below:

3. In the recent call, we clicked the I after the mobile phone number, as shown in the following figure:

4. Let's pull down this person's mobile phone number, as shown in the following figure:

5. Drop down to find the point to stop calling this number, as shown in the figure below:

6. In this way, the number of this overseas phone can be blacklisted, as shown in the following figure: