This is a VERY easy thing to do.
First you will need up upload your pdf to your server using an FTP program of your host’s file manager. You can put it in a sub folder or in the main folder..
Once your image is there, you will want to just make a simple link to that file.. Like this
<a href="https://yourdomain.com/subfolder/filename.pdf">CLICK HERE TO DOWNLOAD</a>
Obviously you will want to replace “yourdomain.com” with your actual domain name.. and if you put it in a sub folder within that domain, you will replace the words “subfolder” with your actual folder name.
The text “CLICK HERE TO DOWNLOAD” can be changed to say whatever it is you want to.. that will be the link that the visitor clicks on to bring up the download box.
If you are doing this within your wordpress post writer, all you have to do is highlight the text you want to link, click the little link button, and put the url path directly to the pdf.. thats THAT easy