Hey! So, the Samsung A16 hasn’t officially got One UI 7 yet. Samsung usually rolls out big updates like that first to flagships and newer phones, then mid-range ones like the A16 get it later.
To get One UI 7 when it’s ready for your phone, just keep checking Settings > Software update > Download and install. Once it’s available for your A16, you’ll see it there.
No way to force it right now without risky stuff like manual flashing, so just hang tight and keep your phone updated!