1.Login to your dashboard--> layout- -> Edit HTML

2.Click on "Expand Widget Templates"

3.Scroll down to where you see </head> tag.

4.Now copy below code and paste it before </head> tag.

<style type="text/css" media="print">
#noprint {display: none;}
// Hide unwanted elements
body {background:fff; color:000;}
// Black text on White background
a {text-decoration: underline; color:00f;}
//Underline Hyperlinks in blue
}
</style>

5.Now again scroll down to where you see this :

<p><data:post.body/></p>

6.Now copy below code and paste it after <p><data:post.body/></p> .

<a href="javascript:window.print()">Print Page</a>

7.Now save your template and you are done.