C# is an object-oriented programming language created by Microsoft that runs on the .NET framework and
C# has roots
If you want more in-depth information, check this out and to walk through tutorials associated with the language, check this out as well: C# tutorials
Now that you know a bit about C#, it's time to run Hello World! Head here: https://www.tutorialspoint.com/codingground.htm and click the language that you want to select. Also, you should be able to see the output of your code on the right of the environment when you feel comfortable running.
Now that you know what some simple website code looks like, here's some more information about what all that code is and what it does:
Information About The Applications of C#
The many things you can build with C#
C# Tutorial - Full Course For Beginners
Follow along with the tutorials and the exercises to familiarize yourself with what C# is
Feel free check out https://codepen.io/pen/ to practice writing and combining what you learned from the W3Schools tutorials!
Hint: If you make a free account, it'll give you a nifty tutorial and you'll be able to see a preview of whatever you're coding!