I work in windows form in visual studio 2015 using c# Language

And I need to generate data matrix to name and phone and address

So that how to do that please using data matrix barcode 2d without using

Commercial library

Are there are any open source or free library can I use it to generate data matrix 2d

Barcode for name and phone and address?

I can do it by qr message toolkit library

But data matrix what I can use which library or c# code I use for generating?

Actually it was all too simple the last time I did simple barcodes. I did not need any library. I needed a BARCODE FONT.
After I installed the BARCODE FONT it was trivial to select the font for use in display or printing.

That takes care of common bar codes. For 2D you should use libraries.
https://sourceforge.net/projects/zintnet/