files to download

i have a zip file i’d like to post online and make available for my wife to download at work. i’ve added a file previously to download, and this file was part of a post where you could click a link to download the file. the new file i don’t want to be part of any story, just a url where my wife can enter it in the browser and download the zip file. for some reason i can’t do that and i am wondering how i can do it.

currently i have mywebsite.com/download/file.xpi where file.xpi is part of a post where users can download the file. so, i put new_file.zip in the download directory assuming my wife could go to mywebsite.com/download/new_file.zip and it would ask her to open or save the file. she we enter the address we get the 404.php file. how do i make it available without a post?