Samsung
Delete a Conversation auf Samsung
Samsung Messages groups every text you exchange with a contact into one conversation thread. Deleting messages one at a time works for a single stray text, but it is slow when you want to clear an old chat completely.
Samsung lets you remove a full thread in one action. This deletes every SMS and MMS inside that conversation, not just the last message you see in the list.
How the deletion works
Open Tap on Messages and find the thread you want to remove. Press and hold it: Tap and hold a Conversation. A selection menu appears at the top of the screen.
Tap Tap on Delete, then confirm with Tap on Move to Trash. The conversation disappears from your inbox and moves into the Trash folder inside Samsung Messages.
What happens after that
Once a conversation sits in the Trash folder, treat it as gone. Content that leaves the Trash folder cannot be recovered, so double-check you selected the right thread before confirming the deletion.
If you only need to remove one text instead of the whole exchange, delete that single message from inside the conversation rather than using this method.