Send some custom messages with shipping details to fedex in woocommerce

I am new to Woocommerce and creating shopping site with wordpress and woocommerce plugin, i am also using woocommerce-shipping-multiple-addresses plugin to ship products to different addresses and using woocommerce-fedex-shipping-pro-2.1.4 plugin to use FedEx shipping method,

the problem is that i want to send some custom messages to fedex when shipping details is send to fedex but i don’t know in which file the shipping details are send in this plugin. i don’t find any file to edit or any other way to do this

Please suggest me, how do i do this. note: i am using latest version of all plugins

Thanks in advance

https://www.ads-software.com/plugins/woocommerce/