Social sharing plugin

Best is a matter of opinion.
Also it really depends on compatibility with the theme and other plugins you’re using. I’d suggest trying a few based on reviews. Then use the one you like the most.

Here’s an article that discusses eleven different social sharing plugins. https://bloggingwizard.com/top-wordpress-social-sharing-plugins-2014/

Once you find one that you like please traffic the thread as resolved.

Happy blogging