Around October and April of every year, Microsoft releases feature updates to Windows 10. Feature updates, unlike quality updates, bring in new features and options to Windows 10.
In addition to adding new features, a feature update bumps up the Windows 10 version number. For instance, when you install Windows 10 November 2019 feature update, it bumps the Windows 10 version to 1909.
By checking the version number of your Windows 10 installation, you can confirm if you are running the latest version of Windows 10 or not. Or, you can tell when the particular Windows 10 version was released.
Check build and version number in Windows 10
Method 1 of 3
Step 1: In the Start menu or taskbar search box, type winver.exe, and then press Enter key to open About Windows dialog.
Step 2: As you can see in the picture below, the About Windows dialog displays the current version number as well as the build number of Windows 10. The version number 1909 indicates that November 2019 feature update is installed on your PC.
If you are running an earlier version of Windows 10 and not the latest version, you can navigate to Settings > Update & Security > Windows Update page and then click on the Check for updates button to download and install the latest version of Windows 10.
Method 2 of 3
Check your Windows 10 version number via Settings
Step 1: Open Settings app either by clicking its icon on the Start menu or using Windows + I hotkey.
Step 2: Click System (Display, notifications, apps, power) and then click About.
Step 4: Here, check the version and OS build numbers.
Method 3 of 3
Check Windows 10 build number via Command Prompt
Step 1: Type CMD in the Start/taskbar search field and press Enter to open the Command Prompt window.
Step 2: At the Command Prompt window, type systeminfo, and then press the Enter key to load information about your computer as well as the operating system. Look for the OS version field. The OS version field here displays the Windows 10 build number instead of the version number.