Instead of trying to hunt through all your messages for a specific one, you can narrow the search by viewing only known or unknown senders. First, go to Settings and select Messages. In iOS 18, go to Settings, tap Apps, and then select Messages. Turn on the switch for “Filter Unknown Senders” if it’s off.
Next, open the Messages app. On an iPhone, tap the Filters link at the upper left. On an iPad, tap the sidebar icon at the upper left or drag the Messages pane to the right. Tap “Known Senders” to see messages only from people you know. Tap “Unknown Senders” to see texts from strangers, including those with one-time codes or verifications. While you’re here, you can also filter the list to see just unread messages.
Source: Robotics - zdnet.com
