How to add our own Headers to a request message

Hello,

We have three different categories of headers.
1.  General,
2.  Request/Response ,
3.  Entity. 

Now, I am trying to add my own headers to the request message.
Where can I add my own headers. Do I need to do this in the libwww code
itself or I should implement independently by calling the functions of
libwww.

Kindly suggest me the how to proceed .

Thank you in advance.

Regards,

Kishore.