string is keyword(blue color) string s = "C-SharpCorner.com"; Console.WriteLine(s); output: C-SharpCorner.com String is Class(Green color) String s = new String('A',5); Console.WriteLine(s); output: AAAAA prints the character 5 times

Both are premitive data type but 'string' is for C# and 'String' for .net framework

There's no difference.

The C# type 'string' is just an alias for the .NET type 'System.String'.

So, as long as you include the following using directive in your program:

    using System;

then 'string' and 'String' can be used interchangeably.