Currently, default Jetpack sharing module doesn’t provides you WhatsApp sharing button. In this lesson you will about a new Jetpack addon plugin that supplies additional Jetpack sharing WhatsApp button for your website.
WhatsApp Sharing Button for Jetpack is the new WordPress plugin that simply enables you to add WhatsApp sharing buttons inside with Jetpack’s social sharing buttons.
Start by installing ‘WhatsApp Sharing Button for Jetpack’ plugin in WordPress
You can only use this sharing button with Jetpack so make you Jetpack by WordPress.com plugin is installed and sharing module is active on your WordPress site.
Now visit your admin area dashboard Settings -> Sharing screen. Scroll down to ‘Sharing Buttons’ section and drag WhatsApp button from ‘Available Services’ box to ‘Enabled Services’ box. Save your changes and that’s it.
If you don’t use Jetpack then read this lesson about adding WhatsApp sharing in WordPress.