Make Files on Records Visible to Customers
Who: Users with collaborator or owner access to the file can change the Customer Access option. Users with view-only access to the file have read-only access to the Customer Access Option. External users can’t see this option.
How: On Files home in Salesforce, from the row-level action list or file preview, click Share. To see where the file is shared, in the sharing detail window, expand the Who Can Access section. The customer access option is visible in the sharing detail of any file shared with a record.
To set the sharing level, in the picklist next to the toggle, select Viewer to give the customer view access to the file. If you choose Set by Record, then the customer’s file access depends on their record access. View access on the record provides view access to the file, and edit access on the record provides collaborator access on the file.
The Customer Access option isn’t available to files shared with users, groups, workspaces, communities, or orgs.