When written notice is required to be given under a provision of this code, the notice may be given either by personal delivery to the person to be notified or by depositing it in the mail in a sealed envelope, postage prepaid, addressed to the person to be notified at that person’s last known business or residence address as it appears in the public records pertaining to the matter to which the notice is directed. Service by mail is considered completed at the time it is deposited in the post office. When a different method of serving notice is prescribed in the code, the notice shall be given as prescribed. Proof of giving notice may be made by the signed statement of an officer or employee of the city or by affidavit of a person over the age of eighteen years showing service in conformity with the provisions of this code or with any other law applicable to the subject matter. When notice is given by registered or certified mail, the United States postal card containing the signature of the recipient shall be sufficient proof of notice under this section.