Filter, block, and delete messages on iPhone
In the Messages app , you can filter messages from unknown senders and block unwanted messages. You can also delete messages and entire conversations.
Filter iMessage messages from unknown senders
Go to Settings > Messages.
Turn on Filter Unknown Senders.
This turns off iMessage notifications from senders who aren’t in your contacts and moves the messages to the Unknown Senders tab in the Messages list.
You canʼt open any links in a message from an unknown sender until you add the sender to your contacts or reply to the message. If the message is spam, tap Report Junk (below the message) to delete and send the message to Apple.
Block messages from a specific person
In a conversation, tap the name at the top of the conversation, then tap at the top right.
Tap the name or phone number to view the contact card.
Scroll down, then tap Block this Caller.
To view and manage your list of blocked phone numbers and contacts, go to Settings > Messages > Blocked Contacts. See the Apple Support article Block phone numbers and contacts on your iPhone, iPad, or iPod touch.
Delete a message
Touch and hold a message bubble, then tap More.
Select the message bubbles you want to delete, then tap .
Delete a conversation
In the Messages list, swipe left on the conversation.
With Messages in iCloud, conversations you delete from iPhone are also deleted from your other Apple devices where Messages in iCloud is turned on. See Use Messages in iCloud.
Note: You can’t recover a deleted conversation.