I think the Questionnaire module would suit your needs. Search "Questionnaire" in the Mendix app store and you'll find it!
My assumption is that you are looking for some way to generate a report using your Mendix data and then export that to a PDF that can be saved. By 'Drag and Drop' I assume that you are looking for some way to arrange the elements on your pdf so the user can customize the report. This type of functionality is extremely complex, so I would encourage you to take this on in small steps. There is not a widget in the app store that creates an entire dynamic drag and drop PDF report builder. Entire companies exist solely to create the types of drag-and-drop custom reports you are looking for, and we do integrate with those using o-data. For example tableau can ingest odata and can build reports for you.
If you want to do this in Mendix, I encourage you to start with a static document. Talk to your users and figure out what data elements makes a functional report, then build a pdf document using the document template builder in Mendix. Without knowing your data it isn't possible to say what the domain model should look like. Use this in conjunction with a excel export to give information to the users.
For some more information about how to build reports in Mendix, check out the following: