Convert Pdf file to a Word document on an iMac, 10.11

Scanned PDF is not same as the usual PDF file, to covert PDF which created from scan, you have to find a convert tool supports OCR function (Optical character recognition). You can search this item in Wekipedia to know more details. I have read an article about how to convert a scanned PDF to word document, it introduced an OCR converter and how to use it to convert your scanned PDF. You can also search other third party application in internet or app store, there are many available choices for you.