Summary

RMO No. 40-2019 prescribes the procedures for proper service of Assessment Notices under Section 3.1.6 of RR No. 18-2013.

Personal service. The notice is delivered personally to the taxpayer at the registered or known address or wherever the taxpayer may be found.
Substituted service or mail. If personal service is not possible, the notice is served by substituted service or by mail. Substituted service is used only when the party is not present at the registered or known address.
How substituted service is done. The notice may be left with a clerk or person in charge at the registered or business address, or with a person of legal age residing at a residence. If no one is found, or the party refuses to receive it, Revenue Officers bring a Barangay official and two (2) disinterested witnesses to attest to this, and the notice is given to the Barangay official with the facts and the witnesses’ names, positions and signatures written on it.
Who serves. The Revenue Officer assigned to the case effects personal or substituted service. Any duly authorized BIR employee may also do so, and disinterested witnesses are persons of legal age who are not BIR employees.
When service is complete. Personal service is complete upon actual delivery to the taxpayer or representative. Registered mail is complete upon actual receipt or five (5) days after the first postmaster notice, whichever is earlier, and ordinary mail is complete ten (10) days after mailing; service to an authorized tax agent or practitioner is service to the taxpayer.

Registered mail complete on actual receipt or after five (5) days from the first postmaster notice, whichever is earlier
Ordinary mail complete after ten (10) days from mailing

Summary by Tax Resources PH. It is not a substitute for the full text of the issuance or professional advice.

RMO No. 40-2019: Prescribes the procedures for the proper service of Assessment Notices in accordance with the provisions of Section 3.1.6 of Revenue Regulations No. 18-2013