如何实现Content-Disposition：附件？

I am trying to make it so that mp3's on my site are downloaded by left clicking instead of having to right click and save as, So in order to do that, I have to set the Content-Disposition: attachment. This is my first website so I am new to how to actually do this, but do I do this in my html markup or do I set this somehow with my hosting site? I am trying to make it so that mp3's on my site