File Download

This may or may not be a wordpress problem I have run into, what I want to is to supply a link to download a file. I have added a directory to the domain root, then inside place the file/s I want to supply to download, so type in https://www.<mydomain>/<download directory>/<filename>. However, if I do that a web page loads with the blog and an error, page not found.
I should know how to do this but I’ve gone totally blank, so I’m assuming I need to add something within wordpresss to get this to work. Any pointers would be appreciated.
Many thanks.