External Sharepoints-AdobeSign classified as dangerous File Sharing Platform by Intellec. Property

Hello, for Security Reasons we should not use the Adobe Document Cloud - as it might be used as a Filesharing Platform - so our Employes can send out Data without any Control. Instead the use of our own hosted external Sharepoints is suggested by our IT-Security / Intelectual Property

What functionality is behind Adobe Sign and Sharpoint?

Where are the documents stored? Only in our external Sharepoint - or are they also uploaded to the Adobe Document cloud.

In other Words - are the additional Buttons for Adobe Sign in Sharepoint only a Service for easy Adobe Sign access and all works as in the Web?  or is there more behind?

Thank you very much    Claus-Peter 

(PS. The Security of the Adobe Document Cloud itself, for uploading Contracts to be send out is not the problem)