The Blood Oxygen application will be installed when the Health application is set up. If you delete the "Blood Oxygen" App after setting it up, you can reinstall it through the AppStore on AppleWatch.
When you set up AppleWatch, you will be asked whether you want to enable the blood oxygen measurement function during the setup process. If you click "Enable" when asked, this function will be automatically turned on and can be used through the blood oxygen application.
Conditions to be met in using the blood oxygen app
1. To use the blood oxygen monitoring function, you need to use WatchSeries6 running the latest version of watchOS and iPhone6s or later using the latest version of iOS.
2. Make sure that the "Blood Oxygen" App can be used in your country or region. You can see this information during the installation process.
3./kloc-users under the age of 0/8 cannot use the blood oxygen application, and the application cannot be enabled when AppleWatch and iPhone are paired with family settings.