Samsung
Turn On/Off Message Delivery Reports auf Samsung
Delivery reports for text messages rely on a small confirmation signal sent back from the recipient's device once the message is stored there. On many Samsung phones this signal is switched off by default, so you never see a status update or checkmark in the Messages app.
The setting lives inside the Messages app itself, not in the general system settings, which is why it is easy to miss. Open Messages ➔ Menu ➔ Settings ➔ More settings ➔ Text messages and enable Show when delivered.
Once active, every text message you send shows a delivered status as soon as the recipient's phone receives it. This works only for standard SMS and MMS, not for messages sent through chat apps such as WhatsApp or Google Messages with RCS, which use their own read receipt system.
If a message never shows as delivered even with the setting turned on, the recipient's phone may be switched off, outside coverage, or blocking messages from your number. Carrier-side delays happen occasionally too, and confirmation can take longer for international messages.