Google +1 button is just like facebook, twitter sharing button where user can share any content on respective social platform. Google +1 button will help others on the web to find the best result when they search on google.
Google +1 button can be add easily in any web page, blog etc.
Follow the steps to add google +1 button in blogger–
Login into blogger–Go to Blogger Dashboard—Design—Edit HTML–Click on Expand Widget Template–Now search </head> tag in the template coding.
Paste below mentioned script just before (above) </head> tag.
Now search <data:post.body/> code and paste below mentioned code immediately above or below, depending upon where you want to place the button.
If you will paste below mentioned code above of <data:post.body/>, you will find the button just below of the post title. On the other hand you will find the button just end of the post body.
<g:plusone size=”small” expr:href=”data:post.url”/>
Google +1 button is available in four different sizes i.e. small, standard, medium and tall. You can choose the size accourding to your requirement. You can also change the location of the button in your blog i.e. left or right, just change in the above bold code.