Users must be assigned a role that has the View Documents permission enabled in order to view attached documents on mobile.

To view a user's current rights, use the People Setup Summary Page. These rights apply to Field View on the web and mobile devices.

Assign document permissions to a user based on their user role. Each user role has its own set of assigned permissions.

Roles can have permission to view, upload, or delete documents. These permissions are set using Business Setup > Security > Roles, selecting a user, and opening the General > Documents section:

Users can view or manage documents that are attached to forms, tasks, process tasks, and assets.