PHP Principal File: You should create a file identified as ‘myhtmlblock.php’ inside this directory. This file will comprise the primary course within your module. CSS is the acronym for "Cascading Fashion Sheet". It's a type sheet language employed for describing the presentation of the document created inside a markup language https://www.presta-addons-modules.com/en/front-office/prestashop-skype-chatcall-support.html