Yes, in the second step (Compose) of creating a certified email, you can choose to attach the same file(s) for all your recipients by dragging them to the “For All” tab of the “Attachments (Optional)” section.

To send different files to different recipients, you must do so via the “By Recipient” tab in the “Attachments (Optional)” section, by dragging and dropping the files into each recipient’s respective box. Files sent to a specific recipient will only be visible to him/her.