To turn on the healthy use function of mobile phone on OPPO mobile phone, you can follow the following steps. First, open the phone's setting options. In the setting interface, find and click the option of healthy use of mobile phone. After entering the interface of healthy use of mobile phone, click the Open button to enable this function. Next, in the current mobile phone interface, select the user, either himself or other family members. Then according to the system prompts, set the password and secret protection issues to ensure the safety of healthy use of mobile phone functions. After completing these steps, you can enter the interface of healthy use of mobile phones and start to use this function to manage the use time and application restrictions of mobile phones.