As mentioned that you have the scanned signature to document in mobile, I believe that you are working with the Adobe Scan mobile app and have the document in pdf format?
If yes, then you can upload the document to the Adobe Reader mobile app and then to the "Document Cloud" storage using the mobile app which that can be accessed from anywhere login into the "Document Cloud" account.
There are other ways to share that scanned doc which are explained in detail here- Working with Scanned Documents — Adobe Scan Help
How to share file form Adobe Acrobat Reader mobile app to "Document Cloud" for that you may see- Adobe Acrobat Reader Help for Android: Print, share, email
Let us know if this is not what you were looking for?