Block texts in Messages on Mac
If you use iMessage to send text messages, you can stop receiving text messages from certain people.
In the Messages app on your Mac, choose Messages > Preferences, then click iMessage.
In the Blocked pane, click the Add button and enter the iMessage address you want to block.
Tip: On your iOS or iPadOS device, block text messages without creating a new contact. See the Apple Support article Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch.
If you’re receiving email messages you don’t want, you can block them in the Mail app. See Block senders in Mail.