Putting Downloadable Files Into WordPress

Easy way:
On the Write post page, scroll down. There’s an upload box where you can put in a file, title, and description of the file, then upload it. This will send the file to your blog. You can upload any file this way.

Once you’ve uploaded the file, there will be options to put a link to that file in your post. Some file types, like pictures, will have special options to allow you to do things like put the images in your post or put thumbnails to the images in the post, etc.