Demand notice by operational creditor: prescribed service methods and mandatory filing with information utility ensure centralised recordation. An operational creditor must deliver a demand notice in the prescribed form or a copy of the invoice with the required notice to the corporate debtor by hand, registered post, speed post with acknowledgement, or by email to a whole-time director, designated partner, or key managerial personnel; a copy of any such demand notice or invoice served must also be filed with an information utility, if available.