Camera setting

Not available in your device

You can add stamp
Select photo
Click on edit (pencil icon)
Stickers
There you can add device stamp !

No official watermark tab in flagship or so called flagship devices

You have to insert it manually by editing images

Open gallery>select any image>click on edit pen>now select stamp/stickers at the bottom>here select calendar like icon>now adjust date and device stamp

How to enable a camera watermark in galexy S21plus 5g