Tap on the side menu to enter the Mail section. When you receive new mail, a red bubble will appear at the top right corner and display the number of unread letters in your mailbox.
Your mailbox consists of system, private, news, and Support sections. The system section can store thirty letters while the private section can store twenty. When you run out of mail space, new letters will replace the old ones.
Tap onto manage your mail.
Guildie gifts, guild honor rewards, and VIP chests will be sent directly to your system mailbox.When your bag is full, some system items will also be delivered through this method.