Tap the letter icon (or contact photo) next to a Gmail message,
then you can tap the Archive icon 
, Delete icon 
, Read/Unread icon 
, Move to icon 
, or the Menu icon 
(Change labels, Add star, Mark important, Mute, Report spam,
and Report phishing) at the top of the screen.
NOTE
You can also tap the Favorite icon 
next to a Gmail
message to designate it as a favorite message.