From the Home screen, tap BlackBerry Hub . Alternatively, swipe right until the BlackBerry Hub appears.
If necessary, tap the Menu icon located in the lower left (e.g. Hub, Notifications, BBM, Text Messages, Email account , Calls, Emergency Alerts) then tap the appropriate email account (e.g. Gmail, Yahoo!, Live, etc.).
Tap an Email message.
Tap Reply or Reply All (located at the bottom; to the right of 'Back').
Enter a message then tap Send (located in the upper-right).