Program.cs
 

using System;

namespace HelloWorld
{
  class Program
  {
    static void Main(string[] args)
    {
      Console.WriteLine("Hello World!");
      Console.WriteLine("I will print on a new line.");

      Console.Write("Hello World! ");
      Console.Write("I will print on the same line.");    
    }
  }
}

Result:
Hello World!
I will print on a new line.
Hello World! I will print on the same line.