How to open oppo black tea mobile phone?

OPPO cooperates with black tea mobile phone to launch OPPO roaming (international internet access). If you encounter problems in roaming with OPPO (international Internet access), you can add the official WeChat account "Black Tea Mobile Phone" or call customer service at 400-900-7505 for handling.

(After ColorOS 3.2, OPPO roaming was renamed as "Internet access") This answer is applicable to all OPPO models.