Hi @kabali_kirubana - it's a good question. Did you try searching here? I couldn't find much either, but I do see that if you are on the latest versions of the Adobe Analytics tag templates, you can see the List vars in the variable mapping interface. So you should be able to use an extension to build a string containing the data you want to send into the desired list var, then map that variable to the desired list var.
Hope this helps - come back with more questions if you need more info!
you can map it in 2 different ways (image below) -
Hope this helps!