Publisher ID is the unique ID which is given to those who holds a Google Adsense account. It is similar to the Roll number allotted to a student. To get an Adsense account you must have quality articles.
Please read a bit and learn how to write articles.
Never lie someone Who trust on you.
Never Trust Someone who lies you.
Regards & Thanks
I would like to suggest you to go through the Help Topics of Techulator and to know what it is exactly and to learn more about the Google Adsense Revenue Sharing.
Once you have an idea about these things, I am sure you will come to know about the Pub Id and its benefits.