Applicable to End Users
In a chat thread, you can select messages to be deleted.
Delete Message in iOS
Open a chat conversation. The messages are displayed in thread view.
Initiate a long-press on a message to delete the message.
(Optional) Select other messages to delete.
Tap Delete.

Select one of the following options:
Delete for Everyone: Deletes the message for everyone, including the recipient(s) and sender.
Delete for Me: Deletes the message for the sender only.

Delete Message in Android
Open a chat conversation. The messages are displayed in thread view.
Initiate a long-press on a message to delete the message.
(Optional) Select other messages to delete.
Tap the delete icon.
A pop-up appears asking you to confirm deletion.
Tap Delete.