Finally we have managed to pass the review process. So, in case anyone can help, what we did was to send an enroll device profile provided by an MDM system (in our case Jamf).

Thank you very much for your answer and clarifications. In our case the app must be controlled by an MDM system and, in this case, it works only for iOS and iPadOS. So we understand that we don't need to ask for MDM capability and we don't need to set the app configuration using a profile. However, it is not clear to us how to proceed when reviewing the app. In the App Review Information we have already specified which keys and values should be in the app configuration and that the app does not require configuration profiles as it is controlled by an MDM system, but we are still asked for a demo MDM profile. We don't know how to get them to review the MDM functionality of the app without using an MDM profile.

Same here

I don't know if this is the best way or not, but I've been trying for a long time to figure out how to solve this problem until I finally realised that the main problem is that the PKCanvasView view must be separated from the PDFView or any other view that contains a UIScrollView and we want it to be superimposed. So, in this case, if we overlay a PKCanvasView and underneath a PDFView, which itself already has a UIScrollView, the moment we want to use the PKCanvasView we must rely on the UIScrollView of the PKCanvasView itself by using its delegate to catch the func scrollViewDidScroll(_ scrollView: UIScrollView) and then synchronise the zoomScale and the contentOffset to the UIScrollView of the PDFView or any other UIScrollVeiw and at all times the two UIScrollView's have to be synchronised.