Updating your OnePlus phone to the latest software version.This instruction is applicable to all OnePlus devices.
The Advantages of System Updates:
Optimizing the system performance.
Extending your battery life.
Developing compatibility with more third-party apps.
Enhancing the system stability.
For Android 10, Go to [Settings] - [system] - [system updates]
Click [check for updates], if there is an update, click [DOWNLOAD&INSTALL NOW]

Update Software Build Manually
Download the updated software build from the OnePlus official page.
For Android 10, Go to [settings] - [system] - [system updates].
Click the settings icon in the top right corner, click on [Local upgrade], find the .zip file and click on [Install] to confirm.
It takes about one minute (depending upon the file size) to update. once done reboot your device to boot into the latest Oxygen OS.
* Pictures, settings and paths might differ from those of your phone, but that do not affect the description in this article.