You can delete any message you have sent, in any chat. You cannot delete messages sent by other people.
How to delete a message
Open the message's menu (right-click on desktop, or press and hold on your phone) and choose Delete. The change is immediate, and there is no confirmation step.
What happens afterwards
The message stays in the conversation, but its text is replaced with a Message deleted placeholder. Everyone in the chat sees this, including you.
- If the deleted message was the latest one in the chat, the preview in the chat list changes to Message deleted as well.
- If someone replied to it, their reply still appears, and the quoted message shows as Message deleted.
- There is no time limit, so you can delete a message at any point after sending it.
{{callout:gold:AlertTriangle}} Deleting cannot be undone. The other person may also have already read the message before you removed it, so deleting is not a guarantee that nobody saw it.
Messages from other people
Delete only appears on your own messages. On someone else's message, the same menu shows Report instead, and you can also block the sender from there. See clearing a chat vs. deleting it from your list if you only want to tidy your own view.
{{callout:blue:Info}} Deleting a message is different from Clear chat and Delete chat. Those only change what you see, while deleting a message changes it for everyone in the conversation.