What is difference b/w Array Class And simple Array

Apart from the fact that one array has three elements and the other has six, there is no difference - both create a one dimensional string array.

However, Array.CreateInstance is intended for 'late binding' - where you don't know until runtime whether you're going to create an array and/or how many elements it will have.

When you do know this at compile time, then the array creation syntax provided by the C# language should be preferred instead.