From your Gmail Inbox, tap a conversation that contains the message you want to read.
The conversation opens to the first new (unread) message, or to the first starred message, if you’ve previously starred a message in the conversation.
Gmail Message Header
Tap to set labels for the message to help organize your messages.
Gmail Inbox Header
While viewing a message, you can tap the message action icons on the Gmail Inbox header or the message header to access the following options: