I would like to track people who click a link that directs them to a PDF file without having to send them to fill out a form first. Is this possible?
Tracked links (the default when you send email from Marketo) always result in a Clicked Email (a.k.a. Clicked Link in Email) activity in the lead's Activity Log, which of course can be used in a Smart Campaign trigger and/or filter. This is basic Marketo functionality!