Using Jetpack Plugin – This is the powerfull All-in-one plugin, it has many modules with many features help improve your website. Each module works as a standalone plugin. If you want to use one of the modules of Jetpack, just active it and use.
Some features of Jetpack:
Site Stats every day.
Edit the custom CSS.
Hide and show a widget on page or post.
Automatically share new post to social networks.
Replace the default comment box, allow the visitor sign-in Wordpress.com, Facebook, Twitter, Google+ account to comment.
Send notifications to visitors when having new posts via email.
Create Contact form.
Create Share buttons to allow your visitors share your posts to social networks.
Support writing complex mathematical equations, formulas, etc.
You can find all the features of Jetpack here. Jetpack is very easy and simple to install and use. After installed, you go to Jetpack ⟹ Settings, there are all the modules for you to choose. Just active which module you like.