I want to know about vitamin d3 in detail which one is the best

They are pretty much all the same except in the strengths. Vitamin D comes in two forms.

Cholecalciferol (vitamin D3) - Yahoo! Health (http://health.yahoo.com/nutrition-supplements/cholecalciferol-vitamin-d3/healthwise--d03129a1.html)

This is a good link to explain this to you.

I take Vitamin D3 every day. About 4,000 units each day. You need to be sure not to take too much Vitamin D3 though each day.