Let me begin by saying I had to dig for this answer (it was time I learned how to do it

)
For an answer, I had to dig through the documentation at my hosting company to find how to do it.
My hosting company has it set up so that I can use my ftp program (I use Fetch) to log into the ftp area that has been assigned to me. Then I upload the files to that area and then in my web page, I put the following line:
<a href="ftp://ftp.csm.lfchosting.com/pub/csm/lorem.rtf.sit">download</a>
It took a bit of fiddling with the url (their instructions didn't reflect reality

) but I did get it to work.
If you try it with a plain text file, it will just open in a browser window rather than downloading it. If you zip or stuf the file first, you'll see it download properly.
Hope this helps. Feel free to try the <a href above - the file you'll get is a .sit and once it's unstuffed it's a rtf file full of garbage.
Take care, Margaret
Margaret