When you block calls, you can block all incoming or all outgoing calls,
and all incoming or all outgoing calls when roaming. Contact your wireless service
provider for more info on blocking specific phone numbers. Depending on your wireless service provider, this feature might not be supported.
In the Phone app, swipe down
from the top of the screen.
Tap > Call
Set any of the switches to On.
The first time that you turn on call blocking, you will be prompted to create a password
to lock your call blocking settings. To change your call blocking password, complete
steps 1 and 2, and tap