you need to Turn off the phone.
* Ensure that the battery power is full or more than 50% on the device.
* Press and hold the “Power Button and Volume Down Button” together for about 20 seconds.
* When the Oppo logo appears on the screen, release both the buttons.
* It will open a Menu page. Then select the “Language” option using the Volume up and volume down keys.
* Press the Power button to confirm the command.
* Select “Wipe Data” or “factory reset” option followed by selecting the “Yes” or the confirmation option.
* As a final step, select Option “Reboot system
The Phone will continue the master reset, taking several minutes to complete. Once done, you will see your phone is brand new. This method of removing the pin pattern or wiping the data can be done on Phone pattern unlock without pc—no need to connect additional devices.