How to check Windows 10 build version

Open a command prompt, or even from start menu, and type:

Now press return. You should see something like this:

You can also use the command:

This will display the list of hotfixes (Windows update patches) installed so far:

Or, you can really elaborate and use:

(Where %YEAR% is the current year, you could filter results by replacing %YEAR% with 2019 to see all updates installed in 2019 for example)