Getting Text from pdf and validate if the form exists

The very nature of PDF's makes it difficult, if not impossible, to validate the internals of the PDF.  There are ways but they are very difficult.  

This is, honestly, your best chance at doing so.  Read this article (https://support.smartbear.com/articles/testcomplete/testing-pdf-files-with-testcomplete/) and see about implementing this if you need to get to the images.