CrestaProject

<a href="https://crestaproject.com/cresta-facebook-messenger-demo-page/" rel="nofollow ugc">Plugin Demo</a> | <a href="https://crestaproject.com/downloads/cresta-facebook-messenger/" rel="nofollow ugc">Plugin Homepage</a>
With Cresta Social Messenger you can allow your users or customers to contact you via Facebook Messenger simply by clicking on a button. Users may contact you directly in private messages on your Facebook page and continue the conversation on Facebook Messenger. 
You can use the floating button which is positioned at the bottom right of the site or a button inside post or pages using the [cresta-facebook-messenger text=”Need Help?” icon=”yes” position=”top”] shortcode. 
Cresta Social Messenger is compatible with WooCommerce and WPML.
Some features
<ul>
<li>Add the button to open Facebook Messenger at bottom right of your site</li>
<li>Use the shortcode [cresta-facebook-messenger] to add the Facebook Messenger button in your posts or pages</li>
<li>Choose which pages to showo the Facebook Messenger button</li>
<li>Mobile version: click the button and automatically open Facebook Messenger App (if installed)</li>
<li>and more…</li>
</ul>
PRO version features
<ul>
<li>Change position of the box button</li>
<li>Change colors of the box button</li>
<li>Add tooltip on the box button</li>
<li>Change box size</li>
<li>Facebook Messenger widget</li>
<li>Different Animations</li>
<li>and much more…</li>
</ul>

Cresta Social Messenger

Allow your users and customers to contact you via Facebook Messenger with a single click.

Cresta Social Messenger vs Chat Widget: Floating Customer Support Button for 30+ Channels, Supporting SMS, Calls, and Chat – Bit Assist