If you want the shorter version. Yes་. You can block unknown numbers from calling your phone. On Apple, go to Settings → Phone → Silence Unknown Callers. After that, calls from unsaved numbers in your contacts will go straight to voicemail. You can still see them in the list of recent calls. [Apple Support†source]. On Android, open the Phone app → Settings → Blocked Numbers and turn on the option to block "unknown callers". This usually includes personal or secret numbers. For spam messages, turn on caller ID and spam messages. Using WhatsApp? Go to Settings → Privacy → Phone → Silence Unknown Callers. Strangers won't bother you. But their efforts will still show up in your call history. 【WhatsApp†Source]. Quick, clean, and ready. 2) iPhone: Block/Silence/Screen unknown callers Random calls from numbers you don't recognize can be annoying. While Apple offers a few tools to deal with this, these steps depend on the iOS version of your iPhone. ...