29 CFR §26.4

1. (a)Electronic service. Electronic service may be completed by
   1. (1)Electronic mail, if consented to in writing by the person served; or
   2. (2)Sending it to a user registered with the Department's electronic case management system by filing via this system. A person who registers to use the Department's case management system is deemed to have consented to accept service through the system.
2. (b)Non-electronic service. Unless otherwise provided by statute, regulation, executive order, or judge's order, non-electronic service may be completed by:
   1. (1)Personal delivery;
   2. (2)Mail; or
   3. (3)Commercial delivery.
3. (c)When service is effected. Unless otherwise provided by statute, regulation, executive order, or judge's order,
   1. (1)Service by personal delivery is effected on the date the document is delivered to the recipient.
   2. (2)Service by mail or commercial carrier is effected on mailing or delivery to the carrier.
   3. (3)Service by electronic means is effected on sending.