Huawei
Enable or Disable Call Barring auf Huawei
Call barring blocks specific categories of calls directly at the network level, which is different from silencing or muting a contact. It works independently of Do Not Disturb and affects every call that matches the selected category, regardless of who is calling.
On EMUI you find this function inside the Phone app rather than in the general system settings. The verified path is Open the Phone app ➔ Open the menu ➔ Open the settings ➔ Tap on More ➔ Tap on Call barring.
From there you can toggle each option separately: All outgoing, Outgoing international, Outgoing calls when roaming, All incoming, and Incoming calls when roaming. Activate only the categories you actually need, since barring all outgoing calls also blocks local numbers, not just international ones.
Your carrier may ask for a password before changes take effect, since call barring is a network feature and not a purely local phone setting. If the toggle fails without an obvious reason, that password is the most common cause.
Call barring is the right tool when you want to fully prevent certain call types, for example while traveling. If you only want silence without blocking the connection, a Do Not Disturb profile or per-contact silencing is the better fit.