Nikon Z 6II Reference Manual page 240

1
Select the desired picture and press the i button.
2
Highlight [Select to send to
smart device], [Select to send
to computer], or [Select to send
(WT)] and press J .
The picture will be marked with a W
icon.
D
Removing Upload Marking
To remove upload marking, repeat Steps 1 and 2.
The i Button (Playback Mode)
198