What is WooCommerce API Manger?
WooCommerce API Manger is used to secure your software with API License Key activation, deactivation and automatic updates of WordPress plugins and/or themes. However it can also be used for some applications outside of WordPress as well, but we will be talking mostly about how to use it with a custom WordPress plugin.
You need to at least make sure you have at least PHP Version 7.00. Here's how you can check from the linux command line:
Type the above command and press enter and you should get results that look similar to this: