I’m writing this for my own benefit as a future reference, and perhaps someone else who can’t find the simple setting to block calls on Windows 10 mobile. You’d think you could simply search settings for the word “Block” and find what you want, but it’s not there.
Note, this is based on my experience using a Lumia 950. Your mileage may vary.
An internet search typically yields old instructions to blocking numbers on Windows Phone 8, which looks like this:
Go into settings, hitting “Call+SMS Filter,” and turn on the ability to block numbers there.
Those steps don’t work in Windows 10 mobile.
To block specific numbers or unknown numbers in Windows 10 Mobile, go to the phone app, then press the three dots in the bottom right corner. Most people would assume you’d then select “Settings” but that is not where you’ll find what you want.
Tap on “Blocked Calls” and finally the hamburger menu at the top left next to the word “Blocked Calls” will give you a menu with three options:
At the bottom you’ll see a “Settings” option which is where you can turn on the ability to block calls with no caller ID, although this seems to work with Unknown calls but not Private calls.
I’m not sure why you can’t find these under the normal Settings menu (if you can, I never saw them!).