The roles you assign users for working with documents allow these users access to the workflow statuses that correspond with their roles. For example, a document owner will see documents in the draft status, a writer will see documents in the collaboration status, and a reader will see documents in the published status. Which documents they can see in each of these statuses depends on a document's assigned security levels, as explained below.
All Users. When a document is assigned this security level, all users with the roles mentioned above can see that document in the workflow statuses they have access to, even if they are not specifically assigned to that document. For example, someone with the document owner role who is not a document's owner can see that document while it is in the draft status, and someone with the reviewer role who is not assigned to a document can see that document while it is in the review status.
Restricted - High. With this security level assigned to a document, only those specifically assigned to one or more stages of the document have access to it. They can also access the document in any workflow status except archived. For example, someone assigned as a document's approver can see that document while it is in the draft, collaboration, review, approval, pending, and published statuses.
Restricted - Severe. As with the Restricted - High security level, only users specifically assigned to one or more statuses of the document have access to it. However, they can only view that document when it is in the status to which they are assigned. For example, an assigned writer can only see the document while it is in the collaboration status.