CrestaProject

<a href="https://crestaproject.com/cresta-help-chat-demo-page/" rel="nofollow ugc">Plugin Demo</a> | <a href="https://crestaproject.com/downloads/cresta-help-chat/" rel="nofollow ugc">Plugin Homepage</a>
With Cresta Help Chat you can allow your users or customers to contact you via WhatsApp simply by clicking on a button. Users may contact you directly in private messages on your WhatsApp number and continue the conversation on WhatsApp web or WhatsApp application (from mobile). 
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-help-chat text=”Need Help?” icon=”yes” position=”top”] shortcode. 
Cresta WhatsApp Chat is compatible with WooCommerce and WPML.
Some features
<ul>
<li>Add the button to open WhatsApp Chat at bottom right of your site</li>
<li>Use the shortcode [cresta-help-chat] to add the WhatsApp button in your posts, pages or custom post type</li>
<li>Choose which pages to show the WhatsApp Chat button</li>
<li>Mobile version: click the button and automatically open the WhatsApp 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>WhatsApp widget</li>
<li>Different Animations</li>
<li>and much more…</li>
</ul>

Cresta Help Chat

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

BasePress

BasePress is the best option when it comes to building advanced knowledge bases on your WordPress site. 
If you use Oxygen site builder to create your posts and pages this add-on is what you are looking for to integrate BasePress Knowledge Base and Oxygen builder!
<h4>Why is this plugin necessary?</h4>
BasePress was developed to integrate with your WordPress theme and it uses its own templates to display the knowledge base content. 
On the other hand Oxygen builder disables any WordPress theme as it doesn’t need one to work and uses its own templates to display your site. In doing so it overrides BasePress templates.
This small plugin adds a new shortcode that can be used inside Oxygen’s templates making BasePress work as expected with Oxygen.
<h4>How to use</h4>
<ol>
<li>Set-up BasePress as normal</li>
<li>Create a new dedicated template in Oxygen for your Knowledge Base.</li>
<li>In the newly created template select the template you want the knowledge base to inherit in “INHERIT DESIGN FROM OTHER TEMPLATE”.</li>
<li>Select the “Knowledge Base” post type under Single</li>
<li>Select “All Knowledge Base categories” under Archive > Taxonomies.</li>
<li>Remove any other option from the template.</li>
<li>Set the template priority higher than other templates.</li>
<li>Edit the Template content by clicking “Edit with Oxygen” and just add the shortcode [basepress-oxygen].</li>
</ol>
If you need to customise a BasePress theme or create your own you can still follow the instructions in these articles: 
<a href="https://codesavory.com/knowledge-base/basepress/basepress-themes/customize-a-knowledge-base-theme/" rel="nofollow ugc">Customise a knowledge base theme</a> 
<a href="https://codesavory.com/knowledge-base/basepress/basepress-themes/create-new-theme/" rel="nofollow ugc">Create a new knowledge base theme</a> 
Just keep in mind that Oxygen would disable any theme in your WordPress installation therefore you cannot place BasePress custom theme on your WordPress theme’s folder. 
You can instead place the custom BasePress theme in WordPress uploads directory.

BasePress Knowledge Base + Oxygen Visual Site Builder Integration

Integrate BasePress Knowledge Base with Oxygen Visual Site Builder

Cresta Help Chat vs BasePress Knowledge Base + Oxygen Visual Site Builder Integration