You can hide or delete the history of a direct message conversation in Google Chat and Gmail.
- Hide conversation—Removes your copy of a conversation. It doesn't remove the conversation from other participants' views. If you hide a conversation and then chat with that person or group again, your chat history reappears (if it's turned on).
- Delete conversation—Permanently deletes your copy of a conversation's history. It doesn't delete the conversation from other participants' history.
Direct message conversations that you delete in Google Chat are also deleted in classic Hangouts, and the other way around. Conversations that you previously deleted in classic Hangouts, before conversations could be deleted in Chat, are not deleted in Chat.
Hide a direct message conversation
Delete a direct message conversation
You can't delete your history for group conversations with 2 or more people.
To delete a single message instead of a conversation, go to Edit or delete a message.