Facebook

Communicate with customers on your website with Messenger-powered chat. Chat Plugin is a chat widget maintained by the Meta Business that enables live chat on your website.
Whether they’re on their computer or their phone, website visitors will be able to message you anytime by clicking on a small Messenger chat bubble in the lower right corner of your site.
Key features:
<ul>
<li>Website visitors can message you while browsing your site.</li>
<li>Set up auto-replies and answers to common questions to serve customers when you’re not available.</li>
<li>Continue the conversation with customers on Messenger even after they leave your website.</li>
<li>Visitors without a Facebook Messenger account can ask you questions anonymously in Guest mode.</li>
<li><a href="https://www.facebook.com/business/messenger/get-started" rel="nofollow ugc">Messenger</a>’s familiar interface builds trust.</li>
<li>No need to switch between apps to answer questions you get on the website.</li>
</ul>

Facebook Chat Plugin – Live Chat Plugin for WordPress

The Facebook Chat Plugin makes it easy for your website visitors to chat with you and ask you questions, even if they don't have Messenger.

teniosgmbh

BrowserCall is a plugin that lets your website visitors communicate with your business through click-to-call functionality. Install TEVOX Browsercall on your website and give your visitors the ability to call your customer service or sales team directly from their browser. 
This software allows you to:
<ul>
<li>Create personal, human relationships with your customers and visitors</li>
<li>Answer questions & provide customer support</li>
<li>Engage in conversations</li>
<li>Build trust and develop relationships </li>
<li>Win customers!</li>
</ul>
BrowserCall is a tool that revolutionizes the way you communicate with your customers. It gives you the ability to communicate with them in a channel that no other company is doing, creating that personal human experience that allows you to provide the highest level of customer service.
In turn, you’ll see less refunds, better engagement which goes directly into your bottom line.
TEVOX enables voice calls through any computer, tablet or smart phone ? right from a webpage. Your customers call through their browser using their microphone. They don?t need to look up or dial or even pay for an outgoing call.
The service is based upon HTML5 features webRTC and WebSocket. There is no need for any plug-in installation or registration/setup needed by the visitors of the website. With Chrome, Firefox already supporting webRTC (and more likely to join in the future), there are more than 1 billion users who can already access this feature in their browser. Calls can be anonymous with no registration needed and users can register or provide their details when additional interaction is needed.
You need a TEVOX account to use the BrowserCall plugin. Register at www.tevox.com for free. You can set-up your routing settings for BrowserCall and receive a Data-Token, wich is needed to authorize your website for BrowserCall and prevent missuse. 
After you have installed the BrowserCall plugin, activate it and fill copy the Data-Toke in the plugin settings.

BrowserCall TEVOX

BrowserCall lets your website visitors communicate with your business through Click-to-Call based on WebRTC.

Facebook Chat Plugin – Live Chat Plugin for WordPress vs BrowserCall TEVOX