You can upload files by using the "Files" tab in the configuration details. Here's how to:
https://qa.h-mdm.com/1925/
After uploading files, you can install a file manager or another related application (PDF reader, Word viewer, etc) which can open a file. The applications are installed through Headwind MDM.
To install an application, get its APK from
https://apkpure.net, then open "Applications" in Headwind MDM, click "Add" and upload the APK. After uploading APK, select all configurations on which it should be installed.