Remove Shipping from PayPal Checkout / Add file to the mu-plugin

Hi, i know there is a couple of topics talking about this but i have a couple of questions relative to the process to add the file that you guys put on here:
https://gist.github.com/wpmudev-sls/2d5e740a9c6024bfefde8aa44ca02b86

i just need to find inside my hosting file manager(cPanel in my case )the folder wp-content/mu-plugin and add that .php file?

and if this remove the shipping option on the check out in PayPal they will understand why this is this way i mean there’s no going to be any kind of trouble with my account to process this action? thanks for you attention.