Windows Security updates you about antivirus protection by viewing you when:

Your computer was last scanned for threats.

Your definitions were last updated- Definitions are files that Windows Security Center Service users to protect your computer against the latest threats.

The computer's performance and health scan was work. This scan ensures your PC is operating efficiently.

You need to customize how your computer is protected with these Windows Security features. To access them, You can choose Start button > Settings > Update & Security. Then choose the feature you want to explore.

Website: https://getassist.net/windows-security-center-service-cant-be-started-error-fixed/