Yes you can. One of the best ways of delivering expanded content is to offer a .pdf as a download, or to have it open up in their browser.
The Media Manager make it easy to upload and insert all sorts of media types into your pages and posts.
Of all things, I personally wrote the instructions in WordPress on this very topic! While it’s written for use by someone teaching a class I think you could get a lot of information out of it as a student.

Some of my clients create a .pdf and offer it as a free download in exchange for an email address.
It’s a powerful form of lead capture.
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