The function of healthy use of the device can help you to know the specific use time of the screen every day, as well as the functions such as "stop time", "available time" and "application restriction". You can set this function by going to I Manager-Utilities-Healthy Devices or Settings-Healthy Devices.
For more questions, you can enter the online customer service of vivo official website-click on mine and enter "Manual" to contact the online customer service for handling.