I did chat with the constant-contact staff about this issue and he referred me here.
If you have some answers with my querry please help me.
What can be the html code or tools to use for this?
Doing what you are asking requires some knowledge of HTML. You can obtain the HTML code from inside of your account under the grow my list page. You would take the code from the HTML wizard and put that on your web-site. From there its up to you or your web designer to implement any further changes with that code. These boards are for our API support which you wouldn't need to do what your trying to accomplish. If I can be of any further help please let me know.