Android
Block a Number from Call History auf Android
Repeated calls or messages from the same number usually mean you need to block the entry, not just ignore it. Android handles this directly inside the call log, so you do not have to open the contact separately or search for the number first.
To block an entry, go to Tap on Phone ➔ Tap and hold an Entry ➔ Tap on Block/report spam ➔ Tap on Block. This works the same way for a plain phone number and for a saved contact, since Android reads the block action from the call history entry itself, not from the contact card.
What happens after blocking
A blocked number can no longer reach you by call or text. Calls get silently rejected, and messages are filtered out without a notification.
If you also choose to report the entry as spam during the same step, Android uses that signal to improve spam detection for similar numbers in the future.
When to use a different fix
If you only want to mute notifications from one conversation without cutting off calls entirely, blocking is the wrong tool. Use the conversation or notification settings for that instead.
Blocking a saved contact through the call log also does not delete the contact. It only stops calls and texts from reaching you, so the entry stays in your address book until you remove it manually.