I’m afraid I don’ quite understand what you’re asking for. but if all you want to do is put a link in a post that downloads a file, then you just insert it via the regular “Uploads” section at the top of where you write your post. The last image (looks kind of lik a star) is for files. Click it, upload your file, and insert the link into the post. That’s pretty much it.
I’m still not 100% clear on what it is you’re looking to do. You want to write a post, and put in a link to download a file, but you don’t want anyone to be able to view the source code/hover over it and see the path to the file? Is that what you mean? but you still want the link to actually download the file in question?
is this something like a “pay for” file? Where someone purchases a download and you want to hide where the file location is so people can’t just go to it willy-nilly? I dont’ know of a WP plugin that can d this, but there’s several PHP programs and services that can.