with this addon you can add messenger chat to your website. This means that vistors on your website will have possibility to send messages to your customer support service. Great way to increase shop usability and make customers experience on your ecommerce page much better.
this is the first available module for PrestaShop 1.7 that offers facebook messenger chat integration.
Several options available in the module allows to personalize it and make it similar to your theme design (colors)
details about module you can find here