You can unsend (undo) a message on iPhone if you’re using iMessage and have iOS 16 or later. Here’s how to do it and what to expect. What you can do

• Undo a recently sent message: If you’re within the eligibility window, you can remove the message from both your device and the recipient’s thread. The other person may still see a notice that a message was unsent, depending on timing and app version.
• Edit a recently sent message: You can edit a message within a certain time window, and the edit will show as such to both you and the recipient.

How to unsend

• Open the Messages app.
• Find the conversation and the specific message you sent.
• Press and hold on the message bubble.
• Tap Undo Send (or Undo/Undo Send) from the menu.
• The message will be removed from the thread, and a note may indicate that you unsent it.

Notes and caveats

• The ability to unsend is available on iOS 16 and later. If you’re on an older version, the feature isn’t available.
• There is typically a time limit for unsending (often a short window after sending); after that window, Unsending may no longer be possible.
• If the recipient has already opened the message, unsending won’t remove it from their view, though the sender’s note may still indicate it was unsent.
• Editing a message is separate from unsending and has its own time limits (commonly within 15 minutes for iOS 16+), with an “edited” indicator for both parties.

If you’d like, specify your iPhone model and iOS version, and I can tailor the steps precisely to your device.