Google+ page give an advantage to products, entertainment, brands, organization and business with an identity and presence in the Google +. If you have Google+ page link that page to your web page. Linking the Google+ page to your site is not only giving you to build relationship with friends and followers, but also give the Google information that is used in your site in Google web search. It is also make you eligible for Google+ direct Contact.
Steps for linking Google+ page to your site:
1. First confirm that your website is available in Google search and is not blocked by Meta noindex tag or by you robots.txt file.
2. Update your home page by adding link to Google+ page like this:
It is best to add the link in most significant page. For example if you have product page then you can add link to the product description page.
3. Links to your website from your Google + page profile
Steps to edit Google+ page profile
a. Make sure you’re on the Google+ page profile.
b. Click on the profile icon.
c. Click on Edit profile.
d. Click Website, if it is editable the color of the section will be blue.
e. Type URL of your home page. It should be same like you added in your Google+ page link in step 1.
f. Clicks save.
4. Check your site with Google, this is optional.
5. Use structured data testing tool to check, it has extracting page information from your content.