From the Home screen, tap the Apps Key > Gmail > Menu Key (in the Front Touch Keys bar).
Tap Settings.
Tap General settings to change the following settings for all accounts.
Archive & delete actions: Choose if you want to display only the archive option, only the delete option, or both options.
Swipe to archive: Select to archive a conversation when you swipe it.
Sender image: Allows the senders image to be displayed beside the name in the conversation list.
Reply all: Mark the checkbox to make Reply all the default message action.
Auto-fit messages: Mark the checkbox to shrink the messages to fit the screen and allow zooming.
Auto-advance: Sets which conversation list is viewed after archive or deletion.
Message actions: Sets when to show message actions.
Confirm before deleting: Mark the checkbox to ask to confirm before deleting a message.
Confirm before archiving: Mark the checkbox to ask to confirm before archiving a message.
Confirm before sending: Mark the checkbox to ask to confirm before sending a message.
OR
Tap an account to change the following settings for that specific account.
Inbox type: Select the default inbox.
Notifications: Mark the checkbox to display notifications for new messages.
Inbox sound & vibrate: Set the notification settings.
Signature: Set the signature you want to include with every outgoing email.
Sync Gmail: Mark the checkbox to automatically sync your account.
Days of mail to sync: Choose how many days of email you want to sync.
Manage labels: Allows you to set the sync and notification settings for your labels.
Download attachments: Mark the checkbox to automatically download attachments to recent messages via Wi-Fi.