S-Drive is sharing-aware, meaning that it will respect the organization-wide default (OWD) sharing settings and sharing rules applied on S3Objects (files uploaded to the S-Drive Tab) and other S-Drive file objects.
Account Files, Case Files, Contact Files and Opportunity Files are set to "Controlled by Parent" in the OWD and cannot be changed. S3Ojbects and Lead Files can be set to Private, Public Read Only, or Public Read/Write.
Sharing rules can be created for file objects that have a lookup relationship to the parent.
Profile permissions for S-Drive file objects must be given to in order for users to access them.
For S3Objects (files on the S-Drive Tab), Lead files and any custom file objects you create which use a lookup relationship to the parent object, you can manually share files and folders using the "share option" on the dropdown action menu.