Hi Mark,
You can include a pdf document in your application by creating an entity that inherits from the file document entity in the system module.
Here is some documentation on this
https://docs.mendix.com/howto/data-models/working-with-images-and-files
Regarding, the pdf containing personal remarks. Would the pdf be generated from the application? If so, you can use a document template to generate a pdf.
Here is some documentation on generating documents
https://docs.mendix.com/refguide/document-templates
If you would need to upload the pdf and some how parse the data from it, that would be a much harder task. You would have much better luck importing a different file format such as excel. The app store has a good excel importer module that you could leverage.
Hope this helps!