Now days users are struggle to find Google Plus Id . It is not like twitter id as your name. Many sites and program needed your Google plus id . This simple steps to explain, how to find your Google Plus id.
Accessing your Google Plus user ID is simple:
>>>Log in to Google+.
>>>Click on the “profile” tab to view your own profile.
>>>IF you look at the URL in the address bar, it should look something like this. https://plus.google.com/100853787161677735910/posts
>>>The long numerical string in the URL is your Google+ ID.
Here is mine from the URL above: