To transfer an account, please open Dokkan Battle Global. Move forward until you can see the starting screen and click DEVICE TRANSFER. [1]

In the next step, please click on Enter Transfer Code [2] and continue. 

Now you can enter the transfer code that you received via automated email. [3]

At the end, just click on OK and follow the instructions.

If you are having trouble with entering the code, click on the following link: