http://twitter.com/share?text=<TITLE>&url=<URL>
E.g. http://twitter.com/share?text=This+is+google+a+search+engine&url=https%3A%2F%2Fwww.google.com
http://www.facebook.com/sharer.php?u=<URL>&p[title]=<TITLE>
E.g. http://www.facebook.com/sharer.php?u=https%3A%2F%2Fwww.google.com%[title]=This+Is%2C+Google+a+search+engine
http://pinterest.com/pin/create/button/?url=<URL>&description=<TITLE>
E.g http://pinterest.com/pin/create/button/?url=https%3A%2F%2Fwww.google.com&description=This+is+google+a+search+engine
image pin it button: my code
<a class="info" target="_blank" data-pin-do="buttonPin" href="https://www.pinterest.com/pin/create/button/?url=<?php the_permalink(); ?>&media=<?php echo $image[0]; ?>&description=<?php the_title(); ?>" data-pin-custom="true"><i class="fa fa-pinterest"></i></a>