How do you need to call it?

I usually use CDN to load some online assets to my views and I use in the href or src for link or script sections of my view.

If you need to load in another way, tell us.

that's the way I want to call it, in a href but I don't know what I have to put or how use it something like href="{{cdn???}}"

well I have my S3 domain where I have my images so I want to call em, but because it's for sure that the domain will change multiple times, I have to made a kind of variable, in my config from cdn to make changes faster but I dont know how to call my stored url from the config

How about using a helper? https://www.keycdn.com/support/laravel-cdn-integration/