Thanks for contacting World Warfare Support.

Tap the arrow icon on the left edge of the battlefield to enable the function area. Tap the envelope icon and select Message. Choose "System" to view friend requests and league invites. 

You can also view friend requests and league invites by tapping "Message" on the right side of the main screen.

Tap the trophy icon on the lower left side of the main screen and you can claim any completed achievements.  Tap your portrait at the top left corner of the screen and click "Medal" on top of the interface and select the medal that you want to wear. You can share some unique medals in chat as well!