To block external callers that have called you:
- Click on the Calls tab on the left side of your screen
- Click on the History option in the Calls menu
- Locate the external phone number you wish to block
- Click on the …(More options) button
- From that menu, click the option to Block
- The number is now added to your block list in your Settings
To block all external calls with no caller ID:
- Click on your person icon in the top-right corner of your screen
- Click the option for Settings
- Click the option for Privacy in the tabs on the left side of the Settings menu
- Under Blocked contacts, select the option to Block calls with no caller ID