Find an email from the sender you want to block and tap it. You have an email address that you would like to block but need to receive a message from that address, you can block it directly by opening your spam settings and entering it in the Blocked Senders or Blocked Domains field. Before blocking a sender in a standard email app, you need to make sure the blocking feature is enabled and then select the option you prefer if you receive an email from a blocked sender.
See also - https://emailspedia.com/how-to-hide-text-messages-on-iphone/
