You can detect interactions with a PDF file on your site via click tagging.
There are four types:
The click's type is set during the implementation.
Please note that once the tag has been implemented, you can use AT Internet's Tag Inspector plugin for Chrome: https://marketplace.atinternet-solutions.com/product/tag-inspector/
You will thus be able to directly review your tagging (this goes for tagging in general not just clicks).
It is up to you to decide on the click type you wish to push based on existing tags and the way you want your data to be displayed in the interface.