The line cout << "Hello, World!" prints text to the screen. The cout object sends data to the console (your output panel). The << operator pushes the text into cout. Whatever you put in quotes appears on screen.
Change "Hello, World!" to "Your Name" and run the program. You should see your name printed. The quotes tell C++ this is literal text, not code. Without quotes, C++ thinks Hello is a variable name.
You can chain multiple << operators to print several things. Try cout << "Hello" << " " << "World"; and you will see the same output. Each << adds more text to the stream.